A.J. Shearsby and the historical geology of the Yass district
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| Dalmanites meridianus, Silurian trilobite, Rosebank Shale, Yass |
During 1982 this author enrolled in an undergraduate science degree at the University of Wollongong, majoring in geology. In the first or second year of study the students undertook an excursion south-west of Wollongong to the Yass and Bungonia regions. The former was well-known for its Siluro-Devonian fossils, whilst Bungonia was likewise a geologically rich area, with a complex array of sedimentary, volcanic and igneous rocks extending from the Ordovician into the Carboniferous periods. During the excursion to Yass a visit was made to a small cliff covered in shell fossils and known as Shearsby's Wallpaper. Move forward to 40 years later (2022), and the author is now retired and resident in Murrumburrah, a small town located approximately one hour's drive north-west of Yass. As such, previous geological studies came to mind, especially when considering the somewhat bland granitoid landscape which forms the country immediately to the north and west of Yass. So it was that during a recent visit to that town a copy of the Life and Times of AJ Shearsby, Yass, 1872-1962 (Bindon and MacQuillan 2016) was purchased as a reflection of renewed interesting in the geology of the area. Arising out of that purchase came the following list of pioneering geological work by Shearsby and others on the Yass district. During 1902-3 Shearsby published a series of 20 articles on geology in the Yass Evening Tribune, and they are reproduced below. The listing is arranged chronologically in regards to events and published material. As such, it tells part of the story of the discovery of a rich trove of Siluro-Devonian fossils on the Yass Plain, alongside a wealth of geotechnical information arising from events such as the Bowning Orogeny.
Chronology
Ancient
Aboriginal dreaming stories tell of volcanoes erupting in the coastal and inland areas of southern Australia. Remnant volcanic cones and other distinct mountainous structures on the landscape of the Yass Plain and nearby region, such as Bowning Hill and Bobbara, form important cultural and ceremonial sites for the local Aboriginal people. Some 25 volcanoes were active on the Australian mainland between 5,000 and 100,000 years ago.
1829
3-4 November 1829: Explorer Charles Sturt, after passing through the Yass region and stopping at Mount Bowning (Aboriginal - Pouni), before returning en route to Sydney on 12 May 1830, comments in his subsequent book on the connection between vegetation and geology, citing the Yass Plains among other localities. Reference: Charles Sturt, Two expeditions into the interior of Southern Australia, during the years 1828, 1829, 1830, and 1831: with observations on the soil, climate, and general resources of the colony of New South Wales, Smith, Elder and Co., London, 1833.
1836
8 November 1836, The Australian, Sydney:
CAVAN.
We have lately had our ears pleased and our imaginations excited by accounts of the discovery, in various quarters, of magnificent tracts of land, fruitful vallies, and verdant plains ; South Australia has been represented as a Paradise - Port Philip as an Arcadia - while the "Australia Felix" just discovered by Major Mitchell beggars description. These announcements are interesting enough to the inhabitants of Sydney and its neighbourhood - whose eyes are accustomed to unmingled monotony of scenery, and to whom any thing that savors of the grand and picturesque is as strange as to the inhabitants of Holland. It is to be regretted that there are not published descriptions of the scenery which may be found in various parts of the Colony, equalling any of those lately presented as appertaining to distant places. Were this the case we should not feel desirous of new scenes - for those within our own limits have sufficient attractions. A Guide Book would on this account be a desirable addition to our works of Colonial Literature. We are promised by an obliging correspondent in search of the picturesque, descriptions of such places in the course of his travels as may be worth note. In particular of the Caves. near Cavan, in the neighbourhood of Yass Plains ; his account will be necessarily long, and to the general reader perhaps uninteresting - for it treats largely of geology and other matters "caviare to the multitude." In the mean time we can venture to give the following brief outline, which will suffice to give a pretty correct idea of the general features of the country: -
From Goulburn to Yass Plains the road is picturesque and interesting. The farther south we proceeded the more beautiful the scenery became ; and, with the exception of two belts of land of about one and a quarter mile each in breadth, I might safely say that we did not cross an inch of bad land (from Goulburn to Cavan), most of it of the very finest quality. It is like passing through a succession of orchards ! Yass Plains are a succession of downs, quite clear of timber, and eleven or twelve miles in extent. There are many, five or six perhaps, of these open spaces which are divided from one another by a belt of trees, so that altogether the plains, or rather the downs, cover a space of thirty or forty miles. The view on some of these hills is very fine, there being lofty ranges at the back, very thinly timbered to their tops (like the western range at Lake George) ; and the cleared land, broken by the belts of trees, looks like a succession of parks. This is the view looking towards the Murrumbidgee. Looking towards Goulburn the ranges are not more than half the height of the Cavan Mountain, but not as thinly wooded. On the edge of the Plain the O'Briens and Mr. Dutton have built very neat houses, having the Yass River running between them, which is there pretty broad. A Mr. Manton has built a house with a very handsome stone colonnade. This view is quite English, and reminded us very forcibly of park scenery at home. From thence to the southward every turn presented a new beauty, and when at the end of ten miles we began to descend the highest range into the valley through which the Murrumbidgee runs, the scenery was beyond description lovely. The river, which is about fifty yards broad, is shaded on both its banks by the she-oak, which grow to a large size, and touch one another. The valley is about six miles long and two broad, and perfectly level and clear. At its edge the mountains at once rise to a great height ; not in a regular succession of ranges, but as if one mountain were thrown by the side of another, or just beyond it, with a total disregard of space, which adds to the grandeur of the scene. Then the geological character of the country is extraordinary. The mountains are composed of limestone ; and whether from some great convulsion of nature, to which many are apt to refer every thing out of the common course, or from causes more natural, the direction and extent of the strata are revealed to the eye. The soil to the very tops of the mountains is beautiful, and the grass grows luxuriantly everywhere. Cavan is the neatest and most gentleman-like place I have seen in this country. No logs of wood about, or broken drays, or ashes, but every thing clean and handsome, with a flower-bed in front, and the soil raked and without weeds ! The greatest attraction of the place are the caves, to one of which, the cave of Talungung, we went. The rock though which the cave is formed is black marble. The water which makes its way through the sides is strongly charged with some solution of lime, which forms the stalactites, the chief wonder of these regions. " Ebden's Altar" is the most remarkable thing in this cave. Mr. Cracroft, a good authority I should think, says he never saw its equal. The whole of it has the appearance of alabaster. The altar is circular, and flat at the top, and about two feet in height; above it is what may be called the drapery, which has the appearance of aloe leaves hanging down within a few inches of the altar. By the bright blaze of a Bengal light, all of us dressed in red shirts and holding torches in our hands, and a black boy standing close to the fire-work, our guide kneeling at the altar with the candle behind it — altogether the scene was romantic and unearthly, and the only sound which at first was heard was the rushing of the water through the cavern, astonishment having kept us all silent.
1840
January - February 1840: Polish geologist Paul Edmund de Strzelecki passes through the Yass district whilst travelling overland from Sydney to Victoria. He gathers fossils along the way and broadly delineates the geology, some of which is described in his Physical Description of New South Wales. Accompanied by a Geological Map, Sections and Diagrams, and Figures of the Organic Remains (Longman, Brown, Green and Longmans, London, 1845, 462p). Fossils noted as from the Yass Plains and described therein include:
* Favosites gothlandica ? (Lamarck.)
* Cephalopoda - Orhtoceras (similar to Orthoceras undulatum Sowerby)
1842
Reverend W.B. Clarke, 19 October 1842, Sydney Morning Herald:
Fossil Bones No.11...... More recently than the exploration of the Isis Caverns, indeed within a few weeks, a very fine series of caverns, filled with splendid stalactites, and much stalagmite, has been discovered on Flyer's Creek, one of the feeders of the Lachlan River, a few miles south of the Conobolas Mountain, about forty miles from Bathurst. These in addition to those which occur in the Yass country, and on the Shoalhaven, make up a very respectable list of caverns; and those persons who have time and inclination, may find, therefore, in various parts of the colony, sufficient ground on which to make discoveries, which will undoubtedly illustrate one of the most interesting problems in geology, and tend to throw great light upon the early history of this vast continent.
1846
Reverend W.B. Clarke, 3 April 1846, Sydney Morning Herald:
Strzelecki on New South Wales.... We cannot resist this opportunity of calling the attention of those who are interested in geology to the facts stated in the journal of that most indefatigable and skilful explorer, Dr. Leichhardt. Persons familiar with the geological structure of the middle and southern parts of Eastern Australia will instantly recognise the features well known to them. There is not one geological fact stated which is not in perfect accordance with what has been discovered elsewhere. The same rocks, or their varieties; the same association ; the same succession ; the same individual phenomena re-occur. There is a continuity of the same general effects of the same persistent laws. The Silurian schists, pierced by granites, sienites, pegmatites, porphyries, &c, of the Dividing Ranges to the southwards ; the still more recent basaltic overflows and outbreaks ; the coralline limestones of Yass, Shoalhaven, and the Allyn ; the conglomerates and sandstones of the Blue Mountain plateaux ; the siliceous and ferruginous coniferous wood of Wollon Hills and Dartbrook ; the coal beds of Newcastle ; the dolomites of the Karua and Moreton Bay ; the quartz porphyry of the Kingdon Ponds and Port Stephens, are all distinctly enumerated in the places in which a theorist would look for them, and in the sequence which a close observer would expect. All confirm the fact, that the structure and composition of this country, as mentioned in a former recent article (on the present subject) are unique and consistent through nearly 1500 miles of direct latitude ; coal occurring within the tropic in the same position and under precisely the same circumstances as at Newcastle, or Brisbane or Bulgo, or Western Port.
1847
17 June 1847, Sydney Morning Herald: Report on the mining of lead near Yass.
1848
James Dwight Dana, 21 December 1848, Sydney Morning Herald: [Extract from fossil descriptions published in the book by American geologist Dana, following a visit to Australia during 1839-40. Posted with comments by Reverend W.B. Clarke.]
Fossil Zoology of New South Wales, No.1 - Zoophyta.
[Favosites.]
F. Gothlandica. (Lamarck.)
Abundant on Yass Plains. Marked with ? in Strzelecki's work, p. 265. It is a Devonian species as well as Silurian. There are other species of Favosites in New South Wales, one of which very closely resembles F. ramosa. F. Gothlandica is one of those species which appears to have an almost ubiquitous range, being found in the Ural and other parts of Russia, in Germany, Sweden, Belgium, France, England, and in extensive regions of North America; it is found over an area in America of not less than 3,360,000 square miles.
S. plicatum (Lonsdale.)
This species, which is described in Murchison's Silurian system, is found abundantly on Yass Plains in weathered blocks. A fine specimen, undistinguishable from the Silurian species, is in the collection of Lieutenant-Colonel Sir T. L. Mitchell.
[There are also fragments of columns and plates of Crinoids in the sandstones of Muree; in the limestone of Binjaberree Creek; at Black Head; Yass; Mulberring Creek; Quarrabolong; Corinda; and Wollongong, some of which are new, and all of which are at present undescribed as from New South Wales. They form part of the collection which was sent to the University of Cambridge. In many of the beds, the columnar fragments are innumerable; in the limestone of Binjaberree Creek and elsewhere, they occur in masses of some square feet, proving how abundant in ancient times these crinoidal animals were in this region of the globe.]
1851
Gold rushes in New South Wales and Victoria give rise to geological surveys. At this time mention is made of the operation of copper and lead mines in the neighbourhood of Yass (cf. South Australian Gazette and Mining Journal, 30 August 1851).
The Reverend W.B. Clarke carries out geological surveys in the region of
Yass and south towards Mount Kosciusko during October - November 1851, with an emphasis on prospects for
gold (cf. The Empire, Sydney, 16 February 1852).
1852
3 April 1852, Sydney Morning Herald: [W.B. Clarke], The Productions and Resources of New South Wales. No.XX - Minerals and Metals - Copper. Refers to copper mining at Yass.
26 June 1852, Sydney Morning Herald: Report on the arrival in Sydney of a sample of gold from the Yass River.
1857
25 June 1857, The Argus, Melbourne: Gold found in the streets of Yass.
29 September 1857, The Empire, Sydney: Opening of the Yass Mechanics Institute highlights the opportunities for education in regards to the study of geology.
1858
6 April 1858, Sydney Morning Herald: Gold found forty miles south of Yass.
1878
23 August 1878, Yass Courier: Charles Jenkins, The Geology of the Yass Plains, Proceedings of the Linnean Society of New South Wales, 1878-1880, Series 1, 3, 21-32. Read before the Society on 27 May 1878. [This is the first substantial published geological description of the Yass district.]
GEOLOGY OF YASS PLAINS, by CHARLES JENKINS, ESQ., L.S., YASS.
The following paper, now issued in pamphlet form, was read before the Linnean Society of Hew South Wales, at Sydney, May 27, 1878. In offering an account of some years labour in the fossiliferous strata around Yass, I must apologise for not giving at present all the detail that may be desired. I find it impossible to accompany this paper with the necessary plans and sections, the result of envoys I have made, without which minute description would be unsatisfactory. I hope, however, in a future paper to supply the information I am now compelled to omit, accompanied by drawings of as many of the principal fossils as possible. It is chiefly of the beds exposed for three or four miles along the course of the Yass River after it reaches the town of Yass that I shall at present treat.
The Yass River enters the town of Yass on the east, then makes generally a westerly direction flowing alike over hard and soft rock, porphyry and shale, just as the dislocation of the strata had marked out for it a course, which it has deepened and widened as best it could. Very interesting are the cliffs on each side. Now we have two hills of porphyry of very different composition, facing each other - the junction of the two porphyries being the bed of the river - then seventy feet of shale and limestone, every vertical foot of which will yield a rich harvest to the geologist. A little further and we have the section of a hill in which the strata broken off on each side are bent in towards the centre, making there almost as acute an angle as the letter V. Again, a little further, and the strata arc reversed, vertical, then contorted in the most varied curve and the former impure limestone changed into marble, marked with pink and other coloured stains in patterns of the sections of the shells and corals it formerly contained.
The main course of the valleys on either side show a some what different origin to that of the river. They are formed chiefly by the scooping out of the softer strata, leaving ridges on each side capped by the more indestructible rock. As the direction of the dip of tho strata is from 20' to 40' south of west, these ridges that flank the valleys present to view in many places as you turn east steep escarpments, and gentle slopes as you look west. They bend round the igneous rock to the west of Yass, forming part of a great curve, not, however, by an uniform sweep, but by jumps, wrenched aside with a sudden twist and interrupted by faults. These faults and twists have given rise to smaller valleys and water-courses, which, in general, mark the limit of the broken and intruded strata.
Wonderful things are those hard rocks that cap the Humewood and Belle Vale ridges. In one place we have an ancient Coral Reef, rich in the most varied Palaeozoic forms, and differing, I imagine, from the Coral Reefs now forming, only as Palaeozoic differs from recent Coral. A little further, and if you are fortunate in cleaving the stone you will have a surface presenting a strange confusion, on which it will be difficult to find a spot not occupied by one of the fossil forms of the varied life of tho old seas. Another will yield hardly anything but Trilobites, jammed together heads and tails so thickly as to render it difficult to procure a perfect specimen.
I will now go back to our former starting point, and take the Yass beds in the order of their deposition. Standing at the edge of the igneous rock (a kind of synetic porphyry) where the river enters the town on the east side, and turning westward, you will look straight across tho fossiliferous strata, which here, with intervening porphyry and altered rock, have a breadth of from four to six miles. The view across the strata is interrupted by tho range west of the town. The mass of this range is Porphyry. This Porphyry naturally divides the sedimentary rocks into two parts - that portion to the east of the Porphyry bending in one direction to the south east over the Yass Plains, and in the other marked by the course of part of the Bango and Fairy-hole creeks, I propose to call the Yass Beds. That portion to the west of the Porphyry, and bending to the south-east over the Yass Plains, and in the opposite direction, west of north, along a course marked by part of the Derringullen and Limestone creeks, to about a mile above the junction of these two creeks, I propose to call the Hume Beds - these beds being so largely developed on the property that belonged to the late Hamilton Hume, Esq., our great explorer.
Starting then on the edge of the Yass Beds, following the river, we have first a few feet of altered strata, a thin layer of limestone, then two feet of fossil bearing strata. Of species obtained hence there are four Brachiopods, including a small Lingula and an Atrypa; three Gasteropoda, including one very like Bellerophon acutus; an impression of a rather large Orthoceras, and a number of very small things not made out.
Then follows some black, slaty-looking shale, cleaving readily in the direction of the bed. These beds gradually become more micaceous and gritty, with an occasional thin band of limestone until they pass into hard compact grit, at a thickness of about 500 feet from the Porphyry. The upper and lower beds of grit are separated by strata of greenish shale: the lower grit is in some parts thin, flaggy, and easily disintegrated, in others compact and rudely jointed.
The lower portion of the grit is in some places full of cubical crystals of oxide of iron. Some of the upper grit has been quarried for building. It exhibits, in many places, distinct ripple marks. The top course is, however, very hard, siliceous, coarse grained, and sometimes almost conglomerate, with signs of altered condition. I have obtained no fossils from the grit. The top of this upper bed affords a convenient means of dividing the Yass Beds into two parts, giving to the lower portions a thickness of about 700 feet.
The next division, the especially fossil bearing half, is best studied by starting from the rock just described at a point where it crosses the river, about a quarter of a mile further down. The strata, after some thin, not very coherent, gritty beds, gradually become calcareous, until they pass into a compact flaggy limestone, just above the Spirifer Beds. The fossils found lowest in this division were a Lingula and a Trochus, succeeded occasionally by an Orthonotus, and some ribbed Spirifers, until at a thickness of about 135 feet we have a small band of black impure limestone, nine inches thick, loaded with fossils. This band at first contains chiefly several species of Murchinsonia and some of Loxonema, succeeded by a layer of Spirifers, and these by a thin mass of Pterinea and Modiolopsis. Among the Spirifers we find here, however, there is no Spirifer Yassensis. That Spirifer cannot be obtained nearer than the Devonian of the Murrumbidgee, in which strata, at a distance of about twelve miles from Yass, it abounds. A Retria, Orthis, and Orthoceras, were also found here.
I will now pass over some flaggy limestone; two beds, from three to four feet thick, of compact sub crystalline limestone, the latter, though full of fossils, yielding little; and some Calcareous gritty beds, to an impure limestone, from which many species have been obtained. The chief fossils obtained from this rock were several species of Spirifer and Atrypa, including Atrypa reticularis, and A. aspera - a Strophomena (dorsal valve convex), a Bellerophon, Bunema, Ecculiomphulus, Maclurea, and a large Helix-like Trochus. Among the Conchifcrs, a large Arca-like species is the most conspicuous. Of Trilobites ; Phacops, and Cromas. This limestone, at Mylora, is overlayed by a flaggy unfossiliferous limestone. The whole thickness of the Yass Beds, near Yass, is about 1000 feet. Dip from 30' to 40' lower division. Dip from 18' to 40' upper division.
We will now stop in our progress across the strata, and turn aside a little to the south. Near one of the lower limestone courses, beyond tho town, I have obtained some very small fossils that help to connect together the different parts of the Yass Bods, and the Yass with the Hume Beds. A head of a small sized Bronteus was found here. Peculiar to this spot is a small, spherical, tuberculated Glabella, having a very Devonian aspect.
HUME BEDS.
Crossing now tho Porphyry, separating the Yass and Hume beds, and starting from where the latter cross the Yass River, and following the westward course of the river to a steep cliff, then continuing in nearly tho same direction across the beds, we shall take the strata as before in the order in which they were laid down. These beds are naturally divided into four parts, which division will answer our present purpose well enough. The first, from the Porphyry to the river at the base of the cliff, near the junction of Boonu Ponds with the Yass River; the second, from the river to the top of the Coral Reef; the third, from the Coral Reef to the Trilobite Limestone; in the fourth, I have not as yet found any fossils. We have first some laminated Porphyry, in which are various fossils, among others encrinital stems of a Lower Silurian type; then a limestone, more developed and richer in fossils, at the Derringullen and Limestone creeks ; then a mass of sub-crystal and altered rock, traversed in one place by igneous rock; then a limestone, composed of thin courses of hard sub-crystalline nodules, weathering yellow, set in a blackish, less pure limestone; then alternations of shale and limestone to the river. From this portion I have obtained the following fossils:
Trilobites: - Cheirurus (Pl. VI., figs. 5, 6, and 7); Calymene (Pl. VI., fig. 4); Spherexochus (Pl. VI., fig. 2); Homalonotus, Acidaspis, Cromus, and Encrinurus.
Brachiopods: - Pentamerus, including (especially to be remarked) P. oblongus (Pl. VI., fig. 3), Atrypa, Rhynchonella, Spirifera, Orthis, Lingula, and Discina.
Gasteropoda: - Murchisonia, Euomphalus, and Bellerophon.
Conchifers: - Orthonotus, Modiolopsis, and Pterinea.
The Pentamerus oblongus is confined to about the lower two-thirds of this division. Cheirurus becomes rare in the upper part; Calceola is found all through. Especially remarkable is it that near the top of this division are two bands of limestone of from six to nine inches thick, containing fucoids. Crossing the river at the bottom of a steep cliff, we have thin courses of nodules and flags of limestone, often concretionary, alternating with shale, which frequently shows the same concretionary structure, gradually becoming more calcareous until it passes into an absolute Coral Reef.
The shale of this division is the richest of any in variety of species. The lower part especially abounds in Pentameri; Atrypa is scarcely less abundant; Atrypa desquamata especially plentiful. Spirifera and Calecola are equally characteristic of this zone. Some of the Spirifers have a very sub-carboniferous look and are like Spirifer glaber. Orthis elegantula, and canaliculata, and a large Strophomena are only found here. The Strophomena, like most of those in the Yass beds, has the Dorsal valve convex in the manner of Strophomena euglypha. Cup corals are everywhere here. Of the wonders of the Coral Reef at the top of this cliff, what shall I say? I have not yet made out one tenth of the species. Among others there are, however, Favositcs, Gothlandica, F. aspera, and Heliolites Interstinctus; all Silurian species.
The next division is characterised especially by the Trilobites of the genera Bronteus, Calymene, and Spherexochus, together with a large Trilobite closely allied if not identical with Phacops longi caudatus which occurs in the top beds. One Calymene is undoubtedly Calymene duplicata. The Spherexochus la almost identical with Spherexochus mirus as figured by Murchison. Size of largest Calymene, 2 1/4 inches in length. Size of largest Spherexochus, 2 inches in length.
The Trilobite in the upper bed (Pl. VI., fig. 1), which is an impure limestone, is chiefly associated with a Petraia. Some parts of this limestone literally swarm with segments of this Trilobite. I have, however, obtained one cast, rather mutilated, of the whole body, and another whole Trilobite doubled up. The head segment of this Trilobite is very like that of Dalmania pleuroptyx as figured by Dana, both in its general proportions and the direction of the facial suture: the furrows on the Glabella are straighter in Dana's figure than on any specimen I have. D. pleuroptyx is a Silurian species, though, like Phacops. Dalmania is both a Devonian and Silurian genus. These Trilobites attained a size of five inches in length exclusive of the spinose caudal appendage.
As I have obtained no fossils in the next division, and as after attaining a thickness altogether of 2000 feet these beds by folds and faults repeat themselves until they reach the Igneous Rocks, I shall not at present trace them farther. In comparing the results obtained from the Yass and Hume beds, I think that there is sufficient evidence in the similarity of the fossils to show that they must both be classed in one formation. I cannot speak of the exact number common to both, but there are certainly among the Brachiopods - two specles of Atrypa, including Atrypa reticularis - several of the genus Spirifera, including two plaited Spirifers, two of Strophomena, and one of Retzia. Of Conchifcrs I believe several, including an Orthonotus and a Pterinea ; a Murchisonia among the Gasteropoda ; of the Trilobites Bronteus and Cromus. There is no doubt about the Cromus ; the Bronteus is, however, in the Yass beds so small, and the markings so indistinct, that it is not possible to speak with certainty, but what can be seen makes it probable that it is identical with that found in the Hume beds.
In contrasting these beds lithologically, the large proportion of grit dividing the Yass beds into such unequal halves, and the absence of those large limestone masses which form so prominent a feature in the Hume beds, are the first things to attract attention. Then we have in the Hume beds an almost entire absence of that somewhat symmetrically transverse jointed structure exhibited in most of the Yass grit and limestone, and instead, a preponderance of concretionary structure in limestone and shale. Then as to the fossils - the absence in the Yass beds of large corals generally, and especially of those masses which are so remarkable in the Hume beds is also to be observed. The fossils of the Hume beds are further distinguished by the number of individuals, large size and variety of species and genera of Trilobites, the number and variety of Pentameri. and by the presence especially of Pentamerus oblongus ; by the number and variety of the genus Orthis, and by two layers of limestone containing Fucoids ; also by their being distributed with an approach to uniformity through a great thickness of strata, whereas in the Yass beds all the fossils are collected in bands which, if taken altogether, would not be more than from ten to twenty feet thick.
The character imparted to fossils of the Yass beds is duo to the great number and variety of plaited Spirifers, and the number of Murchisonia, Bellerophon, and Pterinea. Peculiar to these beds is also a Maelurea, a large Helix-like Trochus, an Eccullomphalus, and a small Trilobite with a nearly globular glabella covered with tubercles.
These differences of the fossils of the two series of beds cannot however, as I think, be considered as altogether marking the characteristics of the different geological periods. The local conditions under which these deposits have been formed have undoubtedly done much to produce the results we now see. When the Yass beds were being laid down, there must have been at least four principal changes of level, two of elevation and two of depression, as evidenced by the double series of bands of grit beds, separated by intervening shale. The waters were tolerably troubled too during the deposition of some of these beds, for some of the upper limestone is full of lumps of shale. These considerations may account for the absence of the larger corals, and together with the fact that many recent species of Trochus, Avicula and Cephalopoda are found between low water and fifty fathoms may explain why the first remains of the fauna of the seas that succeeded the sinking of the old shore - now represented by the grit with its ripple marks - should be such a group as we there find of Modiolopsis, Avicula, Murchisonia, and Orthoceras. That the sinking was interrupted by periods of upheaval seems probable from the thin layer of sandstone covered with Aviculidae that occurs above the strata of Spirifers and Pterinea. This thin layer seems to explain a rather notable thing connected with this Spirifer bed. Evidently, to my mind, these Spirifers were not buried in the order their fossil shells now lie. From a foot below the Spirifers to this sandstone layer everything appears sortcd. First we have a layer of irregular lumps, then one of smaller lumps, often containing a Murchisonia, a Loxonema, and an occasional Spirifer; then a layer of almost uothlng hut Spirifers as c ose together as possible, but scarcely an inch thick then Pterinea two or three deep, but not making a thickness of half an inch : then smaller Aviculidae and sandstone. Does it not seem probable that the temporary rising of the sea bed brought the burial place of these mollusca within the action of the tide, whose ebbing and flowing has sorted them in a manner that no other agent but running water, as far as I know, ever does.
NOW AS TO THE AGE.
It cannot be expected to establish in Australian geology the minute subdivisions it has been found necessary to make in the geology of other distant countries : very unlikely, for instance, that the same breaks should occur here as in England and America. The division of upper and lower Silurian not arising from local arrangement has been made out in all countries where the Silurian system is at all developed. I therefore consider the terms upper and lower Silurian can be used here. The Yass Period or the period of the deposition of the Yass and Hume beds I believe to be essentially upper Silurian, and one portion at least to represent the equivalent to the lower part of the upper Silurian of other countries. No fish bones have yet been discovered, so that at present the Yass period satisfies the requirements of the Silurian formula: a Fauna represented by invertebrates, of which the Articulata are chiefly Trilobites ; and a Flora by Fucoids. To the Trilobites, however, we must look for the most decisive testimony. The fact of Calymene ranging all through the fossiliferous portion of the Hume beds, and Cheirurus and Spherexochus ranging nearly through - these being exclusively Silurian genera, is almost sufficient evidence in itself from which to class these beds as not newer than the upper Silurian : while the absence of any Trilobites of exclusively lower Silurian genera affords a presumption that they are not older, which presumption is strengthened by the presence of O. reticularis and Pantameri. The presence of the large Trilobite closely allied, if not identical with Phacops caudatus and having no resemblance to the Devonian species of Phacops - and of tho Homalonotus which is not of the characteristic Devonian type, all add force to the evidence afforded by the frequent occurrence of the other Trilobites. The only part of a Trilobite with a Devonian aspect I have found in the Yass beds is the Globular Glabella. The variety of Orthidae, of Silurian species, as Orthis elegantula, helps to stamp these beds Silurian. While the abundance of Pentameri, especially the presence of Pentamerus oblongus, support the inference that part of these beds may rightly be considered to represent the lower part of the upper Silurian. The presence of a Maclurea must not be forgotten. Pentamerus oblongus is especially relied upon by Sir Roderick Murchison as determining the strata in which it occurs, in Europe and America, to be the equivalent of the Llandovery of the British Slluria. The Cheirurus found in these beds is Cheirurus insignis, a Llandovery species. (Recherches, sur les fossiles, Paleozoiques de la Nouvelle Galle De Sud, par L.C. De Koninck).
Among the corals we have unquestionable Silurian species, Favosites Gothlandica, F. asper. Heliolites interstinctus. The occurrence of hollow encrinital stems, a lower Silurian type, gives additional weight to evidence in favour of one portion at least being the equivalent of the lower portion of the upper Silurian. The presence of Calceola and Atrypa desquamata cannot be considered to outweigh the evidence drawn from the mass of Silurian species among which they are found. Their presence there is not so remarkable as was the finding, in Bohemia, in the midst of Silurian species, of large-sized Goniatites, supposed before to be no older than Devonian. To these reasons I will add, that in the limestone of the Murrumbidgee, which in places is crowded with many plaited broad winged Spirifers, I have found Spirifer Yassensis, Leptaena subaequicostata, Loxonema anglicum, Niso Darwinii, species determined by Professor Koninck from specimens forwarded to him by the Rev. W. B. Clarke, to be established Devonian fossils; but I have not found a sign of a Trilobite nor one shell common to both the Murrumbldgee limestone and to the Yass and Hume buds.
I will not conclude without some reference to the igneous rocks. They are all chiefly Porphyry, some very like Syenite, and presenting on the hilltops a very granitic arrangement of boulders. Other varieties are numerous, some with a pink felspathic base, and several with rather large crystals of felspar and Hornhlende, and probably Pyroxene. That some of these rocks are newer than the sedimentary beds is evident by the altered conditions of some of the strata in contact with them. Some may be of the same age, for in several places we have the Porphyry enveloping fossils, while in others it is studded with casts, which it has beautifully preserved, while it has destroyed the shells. Of metals, I will merely mention the fact that Galena has been obtained in the Hume Beds at Limestone Creek, near its junction with the Derringullen, and near the Dcrringullen Creek, about three miles from its junction with the Yass River.
In comparing the fossils of these beds with those of the upper Silurian of other countries, the absence of Graptolites is a marked peculiarity. There are, however, abundance of Bryozoan and probably Sertularian forms. It will also be noticed that there are wanting those large forms of Cephalopoda which are usually found in some of the beds of that age. This last fact seems of itself to point out how small a portion the Yass period represents of the Silurian of New South Wales, and how impossible it would be to attempt to fix the exact position of these beds in the Silurian series, until other beds of the like age have been examined as carefully as these have been.
A lithograph plate is appended, of which the following is an explanation:-
No. 1.— Phacops, from the Limestone (Belle Vale, Limestone), upper bed of 3 division. Hume bed.
No. 2.— Sprenochus, from tho Hume beds.
No. 3.— Pentamorus oblongus. Hume beds, lower portion.
No. 4. — Calymene Duplicata. Hume beds. (Lower Silurian, Europe).
No. 5 to 6.— Cheirurus. Hume beds.
No. 7.— Cheirurus Insignia. Hume beds.
The following is a list of fossils, which in Professor de Koninck's work already quoted, are classed as Devonian, and said to be found in the neighbourhood of Yass, but which are certainly not to be found in the Yass or Hume beds. They will all, I have no doubt, be found where I found those marked with an asterisk (*), that is on the Murrumbidgee, in beds overlying unconformably the Yass and Hume series.
Discina Alleghania
Chonetes Hardrensis
Lepiwna Noble
Rhynchonella Pleurodon
Spirifer Multlplicatus
Spirifer Cabedensis
Spirifer Lalisluuatus
Mitchelta Striatula
Nutica Cirrifurmis
Cystoceras Woodsii
Orthoccras subdiminuatum
Murchisonia Turris
Murchisonia Vernuliana
Murchisonia Granifera
Bellerophon convolutus
Pleurotomaria Subconica
Leptama Subaaquicostatu
Spirifer Yassensis
Loxonema anglicum
*Niso Darwinii
--------------
26 July 1878, Yass Courier: The Geology of the Yass District. [Review] L. G. de Koninck, D.M.. P.G.S. Researches on the Paleozoic Fossils of New South Wales, Brussels, 1877. Printed at the Royal Academy of Belgium. 1 vol., and an atlas of plates.
Many of the fossils described by Professor Koninck were collected many years since and forwarded to Mr. W.B. Clarke without any sufficient description of the locality from which they were collected. The words, "neighbourhood of Yass," which occur so often in Mr. Koninck's work, were no doubt in former times applied to a very large area. The following list of fossils, said to be found in the "neighbourhood of Yass," and classed by Mr. Koninck as Devonian, I may say are not to be found in the series of sedimentary rocks that have a breadth from Yass south westerly of from five to six miles, and which are characterised by abundance of Typied Silurian forms : -
Discina Alleghania.
Ohonetes Hardreusis.
Septana Nobilis.
Rhynchonella Pleurston.
Spirifer Multiplioatus.
Spirifer Cabedeusis.
Spirifer Satisinuatus.
Michella Striatula.
Natioa Cirriformis.
Cytoceras Woodisi.
Orthoceras Subdiminuatum.
Murohisonia Turris.
Murchisonia Vernenliana.
Murchisonie Granifera.
Bellerophon Convolntus.
Pleurotomaria Subconica.
* Septana SubeqnicoBtata
* Spirifer Yasseusis.
* Soxonama Anglicum.
* Niso Darwinii.
Those marked with an asterisk I have obtained on the Murrumbidgee, about twelve miles from Yass, where I have no doubt the other Devonian species described by Mr. Koninck will be found. The difficulty of fixing of the boundaries of the different periods referred to by the reviewer does not effect the classing of strata that belong to the more typical portions of the great division, and cannot be any impediment to recognising as Silurian to beds at and immediately to the west of Yass.
The foregoing remarks are supplied by Mr C. Jenkins, surveyor, Yass, than whom no other is a better authority on geological matters connected with the Yass and neighbouring districts, and were written with a view to the introduction of the .... interesting review from the S.M. Herald of Professor Koninck's recent work, the title of which is quoted above....
We owe this most interesting and valuable volume to the zeal and energy of the veteran geologist who has just passed away. It is one of the many monuments to his labours. It may be even said to contain a summary of the result of them. These, in fact, are the result of an examination by one of the most eminent paleontologists of Europe of the fossils collected by the Rev. W.B. Clarke during forty years. It may not be perhaps that all he collected are fairly represented, because this work deals with fossils, and the metalliferous deposits claimed as much of Mr. Clarke's attention as the organic remains. .... And now turning to the subject matter of the work itself, we must say that in one respect it is a disadvantage to have our fossils dealt with by European men of science. Because if any one wishes to know how the question is decided as to the age of the beds from which the fossils are taken, he will be disappointed. This arises from the fact that the author had no information about the beds or the localities. It is true the text is divided into two portions, one of which deals with Devonian fossils and another with those appertaining to the Upper Silurian. Supposing now a geologist has a collection from that very prolific district Yass - prolific in fossils as it is fruitful in other respects - and he wants to know whether they are Devonian or Silurian, he will find that our author gives as the locality of the most characteristic Devonian species - "Yass" - and nothing more, and for the most characteristic Silurian species - "Yass" - and nothing more. True, there are other localities, but as to the beds or their modes of occurrence, or the dip, &c., of the deposit in which they are found there is nothing whatever. Now all this is very tantalising. By far the most interesting part of the information, and the most valuable parts of the information, are left out. It may be said that with the aid of this work the student may find out the most for himself. He can recognise the fossils, and then go and examine the beds, and so by this means find which are Devonian and which are Silurian. Ah, yes! that is if the beds are distinct. But supposing they are mixed together - and this is what some say they are - what are we to conclude ? It may be that our Australian beds have a derivative fauna, and unless the fossils are very carefully marked as coming from such and such strata, with such a dip and such underlying or overlying rocks; to say that they are described species or new species is very little information at all. And we fear now that for unique specimens the information is irrevocably lost. It is hard to say what records may have been preserved by Mr Clarke; but, unless they are to be found amongst his papers, this book has not given any clue. In justice to the author it must be added he has done all he possibly could do without knowing the locality. We have taken Yass as a rather favourable illustration, because the place is well known and the fossils are abundant.
1887
John Mitchell, Notes on the geology of Bowning, N.S.W., Proceedings of the Linnean Society of New South Wales, Series 2, 1, 1193-1204. [Mitchell (1848-1928) was a school teacher at Fort Street Training School, Sydney. He moved to Bowning, north of Yass, in 1883 and developed there his interest in palaeontology.]
1897
Robert Etheridge Junr., The discovery of [Diprotodon] bones at Cunningham Creek, near Harden, N.S. Wales., Records of the Australian Museum, 7 January 1897, 3(1), 9-10. [This find is referred to by A.J. Shearsby in his 1 September 1902 article on ancient Australian animals (reproduced below).]
The Cunningham Creek Gold-field is situated about fourteen miles south-east of Murrumburrah and Harden. The "diggings" lies along both sides of the creek, above and below the Jugiong Road-crossing to Cunningham Plains, reaching almost down to its junction with the more important Jugiong Creek. The whole of this district is composed of grey granite cropping out here and there in bosses and tors, otherwise a thick granitic detritus hides the bedrock completely, and in consequence a subsequent denudation has given rise to gently rolling downs and hills. It is in this detritus that the bones of extinct Marsupials have been found for some time past, generally lying immediately above the auriferous wash-dirt of the old subsidiary branches of Cunningham Creek. The claim of Messrs. J. F. Wilson and Party, who first reported the discovery, is situated on the north bank of the creek, the shaft mouth being about seventy feet above the creek bed, and on the Cunningham Creek Common, barely a mile south-west of Cahill's Hotel. The shaft is down sixty feet in fine granitic detritus, interspersed with large boulders of granite. The bones are usually met with at fifty-eight feet from the surface, and, as before stated, immediately above the wash-dirt, but from the wet nature of the ground, they are all very rotten, and difficult of extraction and preservation. The wash-dirt appears to be of poor quality, although containing a few gem-stones, running in narrow gutters between hard granite bars. The bones procured were chiefly those of Diprotodon. Through the courtesy of Mr. W. T. Ditchworth, the Manager of the Crown Point Gold Mining Co., Ltd., I was able to inspect the workings of the Marshall-McMahon Reef, where a quartz lode carrying free gold, and another with very refractory ore, are worked. I was fortunate enough to obtain good specimens for our collection.
1900
During 1900, A.J. Shearsby, aged 28, '....paid a visit to a geology students' camp at Euralie, led by the late Professor David. A talk with the gifted David so inspired him that a lifelong passion for geology seized him then and there.' (Sydney Morning Herald, 1962).
1902
20 February, Geological formation of the Yass district. Some interesting fossils, Sydney Morning Herald.; Sydney Mail and New South Wales Advertiser, 1 March 1902. Report on delivery of a lecture to the Yass Mechanics Institute by Professor T.W. Edgeworth David of the University of Sydney:
Geology of the Yass District. Last week Professor David of the Sydney University delivered a very interesting lecture on geology in the Mechanics' Institute, Yass. For some days he had been examining the immense Silurian fossil beds at Hatton's Comer and the Devonian group at Cavan. He drew attention to the interesting formations. of ancient corals and volcanic ash which abounded in the district between Yass and Bowning Hill, and said that in past ages active volcanoes were in existence here, and that Bowning Hill group were relics of such. Mention was also made of the rare and perfect fossils to be obtained in the district. The professor said he believed the present trip would be the means of adding several new kinds of fossils to those already known to science. The lecture was illustrated with lantern views; Efforts are being made to obtain a representative collection of fossils for the Mechanics' Institute. Some perfect specimens have been gathered at times.
20 February, Yass Evening Tribune:
Geology. Professor David's Lecture.
It was in a sense unfortunate that only such short notice could be given of the lecture delivered by Professor David of the Sydney University, in the Mechanics here on Monday night, because otherwise the lecture might have been enjoyed by ever so many more people. As is known the Professor and a party, including Mr Pittman - who was present on Monday night, have been "doing" the district round in search of fossils and wonders of the geological world, and on his way back to Sydney on Monday night he was able to spare an hour and a half to give the people the advantage of hearing in a brief way of the many wonderful things - from a prehistoric standpoint, with which they are surrounded here.
The chair was taken by Dr. English, President of the Mechanics Institute, who apologised for the unavoidable absence of the Mayor. A platform had been temporised in the hall, and here was arranged an oil lantern, which threw many views on to the sheet, fixed on the stage. The appointment of all this, as well as the manipulation of the lantern, was done by Mr. Shearsby, to whose zeal in the matter the public are in a great measure indebted for the lecture altogether. Professor David plunged at once into his subject - a subject upon which he is so widely acknowledged a master. He spoke in a general way and from memory, and the very satisfactory audience - larger than was expected - followed him intently throughout. Yes, many wonderful fossils, and many wonderful facts in geology were in evidence round Yass ; one of the most interesting, and in that respect most richly endowed districts to be found in the State. This place has long been known to geologists, was in fact one of the first places selected years ago to begin the demonstration of the geological resources of New South Wales.
Coral was the principal evidence dealt with ; many wonderful coral fossils had been unearthed along the river, particularly round Hatton's Corner; Mr. Shearsby had discovered a very rare and interesting coral sponge. The geology about Yass was very ancient: long ago—millions of years as the scientists reckon - this place was under the sea, hence the coral. In these times the sun shone, as was evidenced by the "sun cracks" to be found below the bridge ; as the tide receded the foreshores hardened and cracked, they were then filled with the fine sand and so the fissures were preserved; here too they found traces of showers of volcanic ash, more particularly marked further down the river. In these days of the forgotten past the busy coral workers built up their habitations about where Yass now stands; out on the Douro race course, the horses galloped over beds of ancient coral. Away towards Bowning, which was also rich in the evidences of these marine wonders, the formation was newer than around Yass; the upheaval there had been at a later date ; still the coral beds were to be found there just as elsewhere.
The same evidences of the work of nature whilst yet the land we inherit rested beneath the sea, were found along the Murrumbidgee, and further on towards Coodra Vale. But the formations there, as explored along in the vicinity of Mr. Jones' place on the river below Cavan, were of a later age still; they belonged to what in geological classification was the Devonian era, whilst Yass was classed in the Silurian period. Around the Cavan district were to be found many rare specimens of fish; his associate Mr. Pittman, had discovered the skeleton of one well preserved ; these fish were peculiar because of the fact that the bones were on the outside, forming a case so to speak, much like that of the lobster of today. These marked the ancient crustacean period in the development of the fish, similar to the discoveries made in parts of Victoria and Queensland; and were especially valuable from the geologist's stand point. They would gather then that the place they now lived in was once the bed of the sea, where Nature worked out her wonders, just as was being done to-day beneath the Pacific, or any of the other great oceans. Time had evolved the land, by the process of volcanic upheaval, and even in that long ago the sun shone and was fairly warm. Beneath and round about them were all these well defined traces of this ancient Silurian age, and here were the abundant evidences ready to the hand of any who would search.
As demonstrating the genius and industry of the coral insect, that sea worker of countless ages still building and building, some plates were thrown on the sheet and explained. Then the Professor turned, in pursuit of his theories, to a brief description of his experiment at the island of Funa Futi, away out in one of the Pacific groups, where he was in charge of the expedition which put down a bore to a depth of over eleven hundred feet to test the coral, particularly with a view to demonstrating the Darwinian theory. Many interesting pictures of the progress of the work, life on the island, the natives and their habits were thrown from the lantern and briefly explained, and the lecturer concluded amidst loud applause about 9.30. On the motion of the Chairman a very hearty vote of thanks was accorded to Professor David for his entirely interesting lecture.
14 July - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.I. INTRODUCTION. (By A.J. Shearsby).
Up to quite a recent date any visitor of inquiring mind who had an opportunity of examining the surroundings of Yass, must have wondered at the absence of a collection of Geological specimens, which would help to give the people some information about the wonderful Geological formations to be seen on every side. When, a short time back, Professor David delivered his interesting lecture on the Geology of Yass, many of his audience must have had an inclination to follow up his remarks and obtain a collection of the fossils which are to be found so plentifully and so close at hand. To collect these interesting relics of ancient life is easy enough, but such a collection is of very little interest to the owner if the names of the specimens are unknown. The great drawback then was to find out the names of the specimens ; once that was overcome, further particulars would be obtained from the many text books now issued. This difficulty is to a great extent removed by the erection of specimen cases in the reading room of the Mechanics' Institute, which are available to all members who may feel interested in the matter. Into these cases have been placed a splendid collection of mineral specimens obtained from the Mining Museum, Sydney, and also a few of the local fossils which I have collected and labelled so that those interested in the Geology of Yass, may be able to start collections of their own which will be a source of education, and help them to spend many a pleasant ramble within a very short distance of the town, besides places many miles farther out. To many people a stone will always be a stone, but the Geologist literally hammers sermons out of stones, for he tells us from his investigations that man has only been resident on this earth a few thousand years, thus agreeing (not disagreeing as some people believe) with the teachings of the Scriptures. Had man lived during the time of the plants and animals of the early Geological periods, his remains would have been found with then) to tell the tale. The living fauna of Australia is, as is well known, different to that of other parts of the Globe. Take for instance the marsupials or pouch-bearing animals which include the kangaroo, bandicoot, wombat, Tasmanian devil, etc. The opossum is of course a marsupial, but is, however, also found in America, and is the only pouch-bearing animal found outside of Australia. Then there is the Platypus, the like of which is not to be found elsewhere. It is not surprising then that many people at first believed that the ancient or fossil fauna of Australia also differed in a similar degree from the fossil fauna of other lands. Investigations have proved that with the exception of some new species, they are identical with the remains to be found in the corresponding rocks of other countries. To illustrate this we will take one fossil which is very common in the Silurian rocks at Hatton's Corner. This is the coral "Favosites Gothlandica." This coral was known in Europe as far back as 1749, when it was described by Fougt as "Corallium gothlandicum," and in 1816 was named Favosites gothlandicum by Lamark. Specimens of this coral were first collected in this district by M. de Strzelecki, who found it at the Yass Plains. The description of this coral will be given later on, together with descriptions of the other fossil remains which find a place in the Mechanics collection.
Professor David and Mr. R. Etheridge, the curator of the Australian Museum, have kindly offered to help me in obtaining a representative collection for our little museum by naming specimens which I submit to them for inspection. Mr. Etheridge informs me that he is at present at work on the fossils from Yass and the Murrumbidgee, and all specimens I send him will be very acceptable as the Museum is short of good Yass material, and there are probably many examples to be found here, which have not yet reached Sydney for determination. I trust, therefore, that all interested will help by collecting and leaving at the Mechanics any specimens they may not require, so that I may sort them out and send them to be examined. There are three different series of rocks in the Yass district which can easily be overhauled, viz., Silurian at Hatton's corner ; Devonian at Good Hope, Taemas, and Weejasper, and the Tertiary formation at Dalton. I hope that before long, specimens from these three formations will reach me for determination & I would point out that in many cases mere fragments have proven of great importance. Hatton's Corner is close at hand for the town collectors and there are many fossils there which have not yet been worked. I noticed on my last visit there that a lot of hunting has been indulged in lately as the rocks now bear the marks of hammer and chisel, which shows that more interest is being taken in local geology than there was a few months ago. To show that there is plenty of scope for the collector, I may state that within the last month I have found several very rare forms and specimens new to the Geologist. I know there are many people who look with contempt on the Geologist, and would try and damp the ardour of the young collector in spite of the good the science of Geology has done for mankind, so I would draw the attention of both friend and foe to the words of Sir Robert Peel:— "Heed not the sneers and foolish sarcasms against learning, of those who are unwilling that you should rise above the level of their own contented ignorance. Do not for a moment imagine that you have not time for acquiring knowledge ; it is only the idle man who wants time everything."
21 July - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.II. HATTON'S CORNER. (By A.J. Shearsby).
We will now gather up our geological implements consisting of hammer, chisel and magnifying glass, and take an outing to Hatton's Corner, a place that is famous for its deposits of Silurian fauna. It is by far the most pleasant walk to be had near Yass and would well repay those who have not yet been there, to spend an afternoon fossicking about, the first opportunity that offers. It is only two miles from town and is reached by going through the nicely wooded paddock at the back of the Hospital. In spring time especially a person would be hard to please who did not enjoy the beautiful glimpses of country you get through the trees, and the wild flowers that carpet the banks of the little creeks that find there way into the larger stream which bears the name of Yass River. Hatton's Corner is a picturesque spot for the artist, who will find studies on all ideas worthy of being transferred to canvas, to delight the eyes of those who have not the opportunity of visiting this place so full of ancient history. Yes, history so ancient that the great Deluge is but an occurrence of yesterday, when compared with the time when the organisms which helped to build those massive cliffs, lived!
A casual visitor will perhaps notice that these cliffs are built up of layers of rock which have the appearance of brickwork; in fact a little way up Black Bog Creek which runs into the river at Hatton's Comer, the low cliffs look like the ruins of the walls of an old castle. The visitor will ask, what is the cause of this formation? This question can only be answered by making a careful examination of the rock which is known as Tufaceous Limestone. Break off a piece of one of the layers and examine it with a magnifier; should the right layer be taken, very little can be made out of it beyond finding it heavy and hard. Careful examination however has proved it to be composed chiefly of volcanic ash. Now take a piece of the layer which lies on top of the previous specimen and you will find it is made up of broken organic remains. Those remains consist mainly of the calcareous stems of animals known to naturalists as Encrinites, Crinoids, or Stone Lilies, together with shells and skeletons of coral polypes. These Stone Lilies belong to the Crinoidea, the first order of the Echinoderms (sea urchins and star fishes) and are true animals. They grew in the form of a large jointed stem with a tassel or lily shaped head. The earliest author who treated of these remains was Agricola (1530), but even a century later their real nature was not clear to investigators. Fossil Crinoids were described by some as petrified plants, fruits, and backbones of fishes; I well remember one day whilst examining a good specimen, an old man coming near saw what I had and kindly told me what they were, said he - "Them's grubs, there's lots over there." He was so certain about it that I did not like to contradict him so I went to where he pointed and got plenty of them. The stem of the Crinoids consisted of a series of flattened discs with a hole in the centre of each forming a canal the full length of the stem. During life this canal was filled with a gelatinous material which ran also by branches of the canal to the lips of the tassel shaped head. The mouth of the animal was in the centre of the tassel and it is presumed that food was conducted to it by means of the cilliary motion of the fringes. It may be of interest to readers of Scott's "Marmion" to learn that "St. Cuthert's beads" consisted of the discs of Crinoid stems! These Crinoids seemed to grow very profusely during the Silurian and Devonian periods, but with succeeding periods dwindled away until now there are only a few to be found living and these have to be dredged for in the ocean. For fuller particulars I would refer readers to Wyville Thomson's "The depths of the Sea" in the Mechanics Institute as it contains interesting information on modern Crinoids.
From what we know about modern Crinoids and corals we may safely assume that the ancient specimens grew in the sea as all modern ones are marine in their habits. This being so, picture to yourselves a vast expanse of ocean in which grew myriads of this early form of life; what a glorious sight it must have been. Beautiful flower like animals with their arms expanded and waving to and fro enjoying their life. But suddenly come the commotion and devastation which accompanies a volcanic eruption. The sky is darkened by ashes and scoria which soon fall and cover up with a thick layer, what was previously a beautiful forest of living beings; myriads are exterminated and their calcareous bodies are broken and heaped together to turn later on into limestone or marble. Many of course survive and multiply on the new bed composed of volcanic tuff, and when a new and luxurant growth has once more been obtained, that also is covered up as its predecessors were. Thus time goes on, eruption follows each successive growth of organic life, and the pressure of the superincumbent rocks combined with the deposition of Carbonate of Lime delivered from the decomposition of various other organisms, cements the mass into a solid laminated block and the result is a mass of Tufaceous limestone similar to that to be seen at " Hatton's Corner."
24 July - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.III. CORALS. (By A.J. Shearsby).
Having collected some good samples of Encrinoids, we will now gather specimens of the corals. It was stated in the last notes that the limestones about Hatton's Corner were formed out of the calcareous skeletons of Encrinoids, Corals and shells. As the fossil deposits in the Yass district have such a large proportion of corals amongst them, a short description or their life history and structure would perhaps be acceptable to many. Corals belong to the order of "Actinozoa," (star animals) one of the low forms of animal life, which were years ago believed to be the intermediate between vegetables and animals. The members of the Actinozoa are peculiar in being able to secrete or build up a hard structure which acts as a framework or skeleton. This skeleton which is left behind when the polyp (as the little animal is called) dies, is what is popularly known as coral. There are several kinds of coral; one of which the Red coral "Corallium rubrum," is so well known on account of it being used for ornaments such as necklets, brooches, earrings. This hard compact coral grows in the firm of a small stunted tree, deprived of its small twigs. This tree which is found from a pale, to an intensely red color, is covered with a thin film of living matter, from which here and there bud out star shaped bodies possessing eight rays or tentacles, in the centre of which is the mouth. This living matter is so delicate that it easily washes off and leaves the bare hard coral exposed. The red coral differs from others as the stars or polyps are not let into the skeleton, which acts simply as a support for the living matter, to rest on. A thin microscope section of this coral shows a series of concentric rings or layers of carbonate of lime, which have been formed by the living mass enveloping it. I have not yet found any fossil specimens similar to this. The red coral is a compound coral, as many individuals live together on the one stem, forming a kind of commonwealth. Another kind of coral is the horn, solitary, or rugose coral. This differs from the preceding one both in habits and structure. It is called solitary when it lives as a single individual and not in a colony like the compound variety. The name horn, refers to its shape, and rugose, to the exterior ridges or "costae" ; as there are many representatives of this coral in the Hatton's Corner fossils, a description of a modern live specimen will be of interest to the collector. Were it possible to obtain a live specimen here, you would observe that the horn coral looked like a small cornucopia, with a beautiful flower at the broad, cup-shaped end. This flower consists of a fleshy disc with an opening in the centre surrounded by rows of tentacles which make it look like a daisy. The central opening is the mouth and the surrounding fringe is called the tentacular disc. It is by means of these tentacles that the polyp collects its food. The living matter of the polyp is so delicate that if the coral is taken out of the water, a few minutes suffice to kill it and there remains only the skeleton with a thin skin covering it. Examine the cup or "calice" of the coral and what do you find? Radiating from the centre are spokes of carbonate of lime. Only their ends are seen, but they run through the full length of the coral. These rays or spokes are called "septae" and the spaces between the "interseptal spaces"; the central column is known as the "columella." The septae where they meet the side of the coral form ridges outside, which are known as "costae." It will be seen then that the coral is not a solid piece like the red coral, but is traversed by channels. During life all these spaces or channels are covered with a skin, so that the coral polyp completely invests the internal apartments of the home which it has built, or more correctly speaking—secreted. To prove this take a live specimen, should you ever be so fortunate as to obtain one, and put it into weak hydrochloric acid. After a while you will find all the solid coral dissolved and there remains a network of skin and filmy substance which when alive pervaded every crack and cranny of the coral and used the hard parts as a support.
There are several specimens of the Rugose solitary corals in the Mechanics collection, and when time permits I intend to cut and polish them, so that the parts mentioned above may be clearly demonstrated. The large specimens belong to the genus Cyathophyllum, and they are being examined in Sydney by Mr. Etheridge for fuller particulars as to their structure and habits, a box of them having been sent by me to the Museum at his request. They are found in fair quantities in the shale underlying the limestone at Hatton's Corner. Being surrounded with soft shale, cleaner specimens are obtained than those which are cemented into limestone blocks. There is room for investigation among these corals, as quite recently I found two specimens, which on being sent to Sydney turn out to be new. One of these looks as if two small horn corals about half an inch long were joined together at their bases and forming an angle; and the other a very small light colored specimen about a quarter of an inch in length and very much resembling a small shell. I have been asked to forward more specimens of these two if obtainable and would be glad to receive any answering the above description, should readers have them to spare.
28 July - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.IV. CORALS - Continued. (By A.J. Shearsby).
Among the many interesting fossil corals to be obtained in and around Yass are two very small specimens which have to bear the burden of very large names. I refer to "Rhizophylluin interpunctatum" De Koninck and "Rhizophyllum Australe" Etheridge, fil. Specimens of these Rugose corals are in the Mechanics collection, and were obtained at the favorite hunting ground at Hatton's Corner. To look at them as they appear in the case, they are most insignificant, and yet when a little is learnt about them they become quite interesting. They are called operculate corals because they possess an "operculum" or lid which closes down by means of a hinge, over the open end or "calice." What pretty little creatures these must have been when alive! The operculum wide open, and the tentacles outspread, gathering in the food necessary for their sustenance. Did this lid act only as a door to shut out foes, or was it used as a trap to close down and hold fast the unsuspecting intruder, who may have, perhaps, been lured to destruction by the attractive, enticing appearance of those brilliant tentacles? They remind one of the trap door spiders which burrow in the ground, and have a lid to block the entrance when danger approaches, or when it has captured its prey.
The two corals mentioned above are the representatives of the only two species to be found in N S.W. and are looked upon as rare, although I have found many in an afternoon's hunt in the shale underlying the Limestone at Hatton's Corner. In the "Records of Australian Museum" it is stated that the operculum of the R. interpunctatum is unknown and that only part of the operculum of R. Australe has been found. I had the good fortune, however, to find some specimens of R. interpunctatum with the complete operculum in situ and sent one to the Museum. The Curator wrote back and stated that it was a very rare condition to find the coral in. These corals resemble the fore part of a shoe with an upturned, pointed toe, and are distinguished from each other by the R. interpunctatum being short and broad and the R. Australe being long and thin. Space prevents a full description.
Very different in structure to the Horn corals are the others which are known as compound or reef building corals, many specimens of which are to be found in the fossil state. These corals require to be strong to withstand the beat of the waves and surf in which they seem to thrive. They are quick growing, light, and strong. They consist of a colony of little cups, each one of which is called a "corallite" — the whole mass being the "corallum" — with the usual star-shaped polyp. Each of these cups grows upwards, and after a while a new structure is formed inside the animal in the shape of a floor or "tabula," which cuts off the lower part and leaves behind the empty compartment. This formation is continued, the polyp in each instance withdrawing into the top chamber, leaving the underlying cells untenanted and dead. A section of this kind of coral will show the "tabulae" cutting the long tubes or corallites into small compartments, each one of which was originally the domicile of a living animal. These tabulae are also the means of strengthening the whole mass of the corallum just as girders are used to strengthen a building. Whilst these corallites are growing, fresh ones bud out from them and grow in a similar way to the main cells, and as they gain in size, outside platforms or "exotheca" are formed on a level with the inside tabulae, and help to bind the corallum into a strong, light mass. When the corallum grows in deep or quiet water, the exotheca are often missing, as the walls of the corallites fuse together instead. An example of the above coral is to be found in the "Favosites Gothlandica," mention of which was made in Part I. The name is derived from "Favus" a honeycomb, and Gothland, a county in Sweden where it was first described in 17419. As the name implies it is similar in structure to a series of layers of honeycomb, the corallites being hexagonal in shape. It is very plentiful in Yass and is found as a rounded mass sometimes elongated. The tabulae are horizontal, and placed at equal distances. In good specimens, along the face of each wall of the corallite, small circular markings are found arranged in two rows. These are known as "Mural pores," and served probably as a means of communication between the individual polyps. The majority of specimens found are, of course, in the form of carbonate of lime, but there is a specimen in the Mechanics which is "silicitied" or turned into flint. This has been caused by being acted upon by water highly impregnated with silica. The carbonate of lime has been dissolved away and the silica deposited in its place. This specimen was obtained in Derringullen Creek, near Belle Vale. It will be noticed that there are several kinds of Favosites corals to be obtained here, some of them being of a very fine tubed variety, and have not yet been thoroughly examined.
31 July - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.V. CORALS - Continued. (By A.J. Shearsby).
Among the loose debris at Hatton's Corner, will be found many flat circular pieces of coral, made up of concentric rings and looking very much like "fossil cakes," at any rate this is the name given them by a visitor who accompanied me on one of may trips. These "cakes" are the remains of a coral known as "Heliotes" (helios, the sun—lithos, a stone). The concentric rings are the result of the manner of growth, when the coral was doing its share in building up the crust of the earth. The coral started life as a small round peduncular object, expanding its upper or living surface; a quiescent stage then followed, which was succeeded by a further active period, giving rise to the next band seen on the base, and so on, each of the concentric rings seen representing a growth stage. There are many specimens of this class of coral in the district which shows how plentiful must have been the growth in those ages so long past. In the face of the limestone cliffs and boulders, and along the banks of the river, will be noticed (polished by the action of wind and water), light colored hard masses of coral showing fine grained and star shaped markings : these corals mostly to the "Heliolites." One of the prettiest of this form of coral is the "Heliotes Megastoma" McCoy. The calice is cylindrical and one-sixteenth of an inch in diameter, and is surrounded by a number of tubuli which are known as "coenenchymal tubuli." These tubuli are believed by some to be nature of aborted polyps, but as they arose regularly arranged in star-shaped fashion round the calice, and like it partitioned off by tabulae, it seems to be more the result of a higher grade of life. This coral I consider to be one of the prettiest to be found in the district.
When I first started hunting up Yass fossils, I was a bit puzzled in being informed that there were many specimens of "Fossil Mushrooms" to be obtained at the Corner. I never succeeded in finding one, but those mushrooms were still talked of and I had to satisfy myself with the ordinary edible species which grow very plentifully there in their season. However I was promised a fossil one, and at last it was produced and the mystery vanished, and it turned out to be a coral "Mucophyllum Crateroides." It is a new genus of coral only lately described by Mr. Etheridge, and it certainly looks something like a mushroom, but as I used to think it was more the shape of a limpet shell I am not surprised at not knowing what was meant. There are several specimens of the above to be seen in the Mechanics' collection. There is another coral to bee found associated with the above, and that is the "Tryplasma." This coral consists of long rugose stalks, and when massed together they look something like Encrinoid stems. They are, as a rule, thicker, being about a quarter of an inch in diameter, and a foot or more long, and are not divided into discs like the encrinoids. Doubtful specimens may be compared with those in the Mechanics.
There are two other specimens corals in the Mechanics case which might cause some confusion to the new collector, as they are labelled "Stromatopora. De Koninck in his work on N.S.W. fossils states them to be sponges ; but they are now considered to be a low form of coral life. Both of these specimens were collected in Derringullen Creek. It will be seen from the hurried description of a few corals collected here, that at one time the ancient district upon which Yass now stands, must have been a vast expanse of sea thickly dotted with coral reefs. That these reefs were in existence for a long period can easily be seen on a short examination of the limestones. Corals do not grow and reach maturity in a few days, so that to allow time for the growth and death of all those layers or bands of corals, and the deposition of the intervening Tuffs, untold ages must have passed before the coral life was entirely extinguished. As a fact it is stated by geologists that the time when Hatton's Corner was a mass of living coral reefs, must have been fully 500,000,000 years ago.
4 August - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.VI. EARLY IDEAS CONCERNING FOSSILS. (By A.J. Shearsby).
In the case at the Mechanics Institute is a specimen marked "pseudo-fossil" which in plain language means that it is not a fossil at all. It looks at the first glance similar to the fossil head of an Encrinoid, but on closer examination it proves to be simply the calcareous or limy cast of the form of an unnamed Favosites coral. Many pieces of rock are to be found which taken the form of organic remains such as fishes, fruits, etc. One case comes to my mind in which a geologist on a visit to one of the opal fields of New South Wales was informed by a resident, that he had a complete fossil fish. He had given £10 for it as it was such a rare thing, and he wanted the visitor's opinion on it. On inspection it proved to be a "pseudo fossil" - being a piece of common opal, shaped like a fish, and as far as value was concerned was not worth more than a shilling or two. Many years ago great controversies were started relative to fossils, as the people did not understand them at all. Many amusing explanations were offered by the biggest authorities of the day, some of which are mentioned below. For the following examples I am mainly indebted to Zittel's "History of Geology," a copy of which is in the Mechanics Library.
Avicenna (980-1057) suggested that fossils were unsuccessful attempts of nature, the form having been produced but no animal life bestowed. Leonardo de Vinci (1452-1519), formed opinions remarkable, for their clearness and correctness. He stated the organisms in the earth in the form of fossils had actually lived where we now find them. He ridiculed the idea that they could have taken origin under the influence of the stars. Agricola (Geo. Bauer) referred to fossils as "solidified accumulations from water." About 1557, Fallopio, the anatomist, actually went so far as to call the fossil teeth of elephants earthy concretions and shells the results of fermentations and exhalations from the earth ; while the pots from Monte Testaccio in Rome he stated were natural impressions in the earth! Mercati, about 1719, concluded that they took origin under the influence of the stars. M. Lister believed rocks produced fossils themselves and in 1671 denied that fossils could have proceeded from animals. Another Englishman, Edward Lloyd, stated fossils were developed from the moist seed bearing vapors which rose from the seas and entered the strata of the earth! A semi-tragic, semi-comic event brought all this controversy to a close. J.B. Beringer, a professor in the Wurzburg University in 1726 published a work on geology. In it a lot of true fossils were illustrated, and besides these were some remarkable forms, in the shape of suns, moons, stars, and Hebraic letters, described by the professor as fossils. As a matter of fact his pupils who no longer believed in the myth of self generation of fossils in the rocks, had buried artificial forms in the earth, and during their field excursions had dug them out in the presence of Prof. Beringer. The Professor was completely duped and it was only when Beringer's own name was discovered apparently in a fossil state that the mystery was revealed to him. He tried at once to buy up and destroy his published work ; but he was too late and in 1767 a new edition was published and the book is preserved as a scientific curiosity.
Many of the false fossils are to be seen in the University collections at Wurzburg Munich, and other places. Thanks however to the close study of several English and Continental geologists, things were so much advanced that by the middle of the eighteenth century, no man of learning believed that fossils were the products of the earth itself. No sooner had the organic origin of fossils been proved, than many stepped in and claimed all fossil forms as remains of earlier life interred during the deluge. These people were known as "Diluvialists" and formed a powerful party, being supported by the church. Among the few who thought otherwise was an Italian, Ant. Vallisnieri, who protested against the idea that the flood was the destroyer of all pre-existing organisms. He pointed out the presence of marine deposits in various countries, and argued that they proved the existence of ancient seas, whose inhabitants as they died fell to the bottom and were fossilised. That he was correct has since been proved by the careful searches made by the modern geologists, and the various fossils are now the means of determining the age of the strata in which they are found.
11 August - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.VII. FOSSIL SUNBEAMS AND TRILOBITES. (By A.J. Shearsby).
It has been mentioned in previous notes that the Silurian rocks which are so intimately connected with Yass, are of great antiquity, so ancient in fact that many people feel inclined to doubt that the sun ever shone during their formation. It is then that the geologist steps in with one of his sermons, to try and convince them that in those times the sun really lighted and warmed the earth. Let us take a walk down the Yass River and when a little past Cliftonwood House, we will find a small cliff of bedded or laminated rock. Here we will find some good examples of "sun cracks." In pre-historic times as now, the sun and moon caused the tides, and when the water had receded from the shore it left the beach of mud and sand exposed to the hot rays of the sun, which dried up and cracked the exposed surface, just as the ground gets cracked now-a-days when exposed in a similar manner. When the water returned, it brought suspended in it sand and other heavy matter which at the first opportunity was precipitated, and tilled up the cracks and prevented them from closing. This then is the cause of many of the ridges and markings to be found on the surface of the slabs which can easily be obtained at the place mentioned.
These "fossil sunbeams" then, are put forward by the geologist as proofs of sunshine in the early days. But some people will argue - those cracks may have been caused through the action of wind drying up the surface and thus forming the cracks." Therefore not being able to convince them with that illustration, the geologist points out the luxuriant growth of corals, shells, &c., of which remains are to be found on all sides, and also the remains of higher forms of life, in the shape of "Annelids" (earth-worms) and Trilobites; all of which he points out required light in order to live. This, however, does not convince them as they will probably refer to the fishes and spiders, which are to be found in some of the vast caves, and state that they do not require the light to exist, and therefore they cannot see how the existence of corals and Trilobites, can prove that the sun shone during their lifetime. Now is the geologist's chance, and he makes the most of it. He obtains specimens of the fishes and spiders which are to be found in the deepest recesses of the dark caves, and submits them to a careful examination. What is the result? Well, he finds that the modern cave specimens do not possess eyes! This being the case they do not need light, and therefore lived in the caves where no light reached them. He then takes a Trilobite - say one from the Silurian rocks of Yass - and placing it before the sceptics, states that is one of the main proofs of his ancient sunlight theory. They are still in the dark as it were, and cannot see the force of the argument as they have not carefully examined the Trilobite which has been placed before them. It is then that the geologist triumphantly points out to them, that the Trilobite possessed eyes! Now, says he, what are the eyes used for but to see with? And also, for anything to see, it must have light; therefore, if you find an animal with eyes it proves conclusively that it lives where light can reach it. This being so, the Trilobite possessing eyes, must have had light in order to make use of them ; and not being able - as far as we can tell - to create an artificial light, it must have depended on the sun as we do, for its great source of light. Not only does the Trilobite give evidence of sunlight during the Silurian period, but it also proves it to have been in force long before that time. There are two older formations of rocks than the Silurian, viz,, the Cambrian and the Laurentian ; the latter being the most ancient. No traces of Trilobites have so far been found in the Laurentian series, but in the Cambrian they are found in threat, numbers. Even those ancient animals had eyes, from which fact the geologist infers that during the Cambrian epoch the world was bathed in sunlight which was perhaps of a greater intensity than we receive now. There is no room at present in the Mechanics case for a specimen of the sun cracks, but I hope before long that more room will be provided so that a really representative geological collection may be placed on view.
14 August - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.VIII. TRILOBITES. By A.J. Shearsby.
There are few fossils which are likely to arouse more interest than the Trilobites ; and as they are to be found in very large numbers in the Yass district I think that they deserve more than a mere passing notice. Naturally the first question that would occur to any one would be, "What are Trilobites?" They are the remains which are found of the ancestors cf our present Crustaceans, which include such animals as lobsters, crabs, shrimps, &c. They however differ from the modern crustaceans, and form a distinct order themselves. No living examples are to be found, they having died out ages ago. In this they differ from the corals and crinoids, as specimens of these are, as pointed out before, to be found existing at the present day. The name Trilobite describes the appearance of the animal, as it means "three lobes", the body being divided into three divisions by two longitudinal furrows. They are a very ancient race, for their remains are to be found very plentifully only in the oldest formations, and no traces are to be seen of them in the more recent rocks. During the Cambrian epoch they lived in a well developed state, but as time went on they increased in number, so that by the time the Silurian rocks were being formed, they seemed to have reached the high-water mark of their existence, as there are more remains to be found embedded in that series than in any other. The next period, the Devonian, they seem to have decreased so much in numbers that only about half the number of species have been found. They still continued to die out so rapidly that during the Carboniferous era - the period following the Devonian - only about a dozen species have been discovered ; and by the end of this last period the Trilobite had ceased to exist. As it disappeared there came instead a crustacean now known as the "Prestwichia" which from its structure and appearance seems to be the connecting link between the ancient Trilobite and the modern "King Crab," which forms an article of food at the present day in the East-Indies. Besides being divided into three lobes by the longitudinal furrows, the Trilobite is divided into three sections in another direction forming the head, thorax, and tail, this last section being known as the "Pygidium". The tail which is triangular in shape is the most common part of the animal to be found. Each of these parts are of course divided into three by the furrows mentioned above. The three portions of the head consist of the "Glabella" or central lobe, and the two cheeks. These cheeks bear the eyes on which so much stress was laid in the last notes. These crustaceans had their bodies protected by being encased with a horny - or chitinous - "crust", articulated or divided into segments which gave them the power of bending themselves as a lobster does. It is believed, from the way in which some specimens are found, that some could roll themselves into a ball-shaped mass. At the end of these segments were the swimming feet, as the Trilobite was a marine animal and spent its time in the oceans then in existence. Traces of a breathing apparatus have also been discovered in the shape of spiral gills.
It will be seen then that the Trilobite was a great step in advance of the corals which were contemporaneous with it. The eyes of the Trilobite however are one of the most wonderful structures to be found in the fossil state. I mentioned them in the last notes as being one of the main proofs of ancient sunlight. Many people would think that these organs would have been destroyed altogether after all the years that have passed since the Trilobite lived and died. On examining the fossil specimens which are obtained, it is certain that the eyes were similar in constriction to those of the crustaccans and insects of the present day. The human eyes are single eyes, but those of the Trilobites and insects are compound - that is, they are constructed of many simple eyes bunched together and acting in unison. Each one of these simple eyes possesses its cornea, with crystalline lens and pupil, forming a cone ending with the optic nerve. These eyes pressing together as a rule take the form of six four-sided facets, so that when magnified and viewed from before or behind, look very much like honeycomb or wire-netting. The compound eyes then are similar to a series of telescopes fitted close together, and in some insects, Trilobites and crustaceans, the number of them reaches a very large figure. Take for instance the eye of the common house-fly, each of the two large compound eyes contain no less than 2000 distinct facets. The eyes of some butterflies have as many as 17,000. Our deceased friend the Trilobite also possessed a large number. One genus "Phacops" had upwards of 200 lenses ; another kind, "Aeglina," had over 1500 ; and it is further stated that the eye of "Brontes Paliler" had more than 30,000. It will be seen then that the eyes of Trilobites are most interesting, showing as they do that the eyes of the Silurian period were as perfect as those of the modern insects and crustaceans.
18 August - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No IX. TRILOBITES - Continued. (By A.J. Shearsby).
When at school I was taught that there was an exception to every rule. Why there should be I could not understand; but even in the case of Trilobites having eyes there is an exception, for during the early Cambrian epoch there lived, strange to say, a Trilobite known as the "Agnostus" which seemed to be of a much lower organisation than the others. The head and tail were very similar, thus differing in a marked way from the ordinary Trilobite, besides there were no signs, even rudimentary, of eyes. One would naturally begin to wonder if this was a sign that the earth was in darkness at this period, but living at the same time as the Agnostus was was the giant Trilobite known as the "Paradoxides," which possessed very large compound eyes. It may be noted that Trilobites are to be found varying in size from almost a microscopic size to the Paradoxides, which grew very large, as specimens have been unearthed which attained two feet in length. The Silurian Trilobites are found to be as a rule more ornamented than in the latter rocks, as many are found covered with knobs and spikes. As the race died out they got altered into plainer individuals, for the latest ones have no ornamentation to boast of. Having learnt a little concerning these most interesting crustaceans, the next thing to do will be to find out where they may be obtained in the Yass district.
Less than a mile below the Yass Bridge on the right bank of the river, nearly opposite Cliftonwood house, the spot that I mentioned before as a good hunting ground for fossil "Sun cracks," we will find forced up by the bedded sandstone, a layer of limestone composed mainly of the remains of shells, corals, and Trilobites. On the surface of this layer will be noticed many good impressions of the objects we require. The rock is rather too hard to allow them to be removed, but wax impressions may be taken of them. By doing this I have obtained some very good plaster of paris casts, which when colored look just as well as the originals. Lower down the river at the geologist's treasure store, Hatton's Corner, is a vast expanse of shale underlying the limestone cliffs, which so far seems to have had very little attention. As usual the parts most commonly found are the tails, and even these require some hunting to obtain in a good state, as the shale is so brittle that many a good specimen is broken to pieces beyond repair. A cast of a complete one is in the Mechanics case, and was obtained here. It belongs to the genus "Cromus" and is peculiar in having little knobs distributed over its body. As this form of Trilobite has not yet been worked, I would ask collectors to keep their eyes open for them. To find the Trilobite in all kinds of positions, such as curled up, lying at full length, and in fragments, you need to hunt well amongst the rocks until you find a place which seems as though it had been a national burying ground. In some places their remains are so thickly deposited that the bodies are matted together. The richest deposit that I have yet found is at Rainbow Hill, about a mile beyond the Corner. To reach it you have only to follow the track which takes you to Euralie homestead, and just before you come to what is known as the Green gate there is a hill or "escarpment" to the left, which on inspection is found to be bow-shaped — hence the name Rainbow. Starting at the end nearest the road it will repay the collector to work round the crown of the hill. Almost every rock - which is a kind of mud-stone - that you break open, shows remains of the Trilobite "Hausmannia Metidionalis," specimens of which are in the Mechanics. The tails to be found here are about as perfect as you could wish them to be, as they show all the segments plainly. Not only do you find the tails but also the heads, and I have found several complete, though slightly distorted specimens about four inches long. Splendid specimens of their eyes are also found and with the aid of a magnifying glass the separate facets can be distinguished. They are large eyes and each contain from 32 to 40 or even more rows of lenses with an average number of say eleven in each row, making 400 and sometimes more lenses to each eye. This Trilobite is to be found in the ridges of mud-stone which run in an irregular direction from Humewood, through Euralie, across Yass River, by Springmount and Galvin's, and towards Bowning.
In fossil hunting in the Euralie paddocks I would advise the collector to do it without the aid of dogs, otherwise there is a chance of coming home minus fossils, and perhaps dog also. The Hausmannia is also to be found in Victoria near Kilmore, and in Tasmania at Zeehan ; so that there is a probability of the ancient sea being so vast that it extended far beyond those places. Accompanying the Hausmannia will be found several kinds of " Horn" corals. Another place which seems to be exceptionally rich in remains of Trilobites is Bowning. Not having the opportunity of fossicking at that place at present, I would be glad if some of the residents would assist by obtaining a few for our specimen case, especially as one form has been named after that village. I refer to the "Odontopleura Boningensis." Being one of the Silurian Trilobites it is extravagantly ornamented with short spines. It has very small eyes, and is altogether much smaller than the Hausmannia. It is to be found plentifully in Bowning Creek, together with many others of the same species amongst which may be mentioned the "Odontopleura Jenkinsi," so named after Mr. Charles Jenkins, a gentleman who was a well-known Yass identity. Another Trilobite to be found at Bowning, a specimen of which I would like to see in our collection, is one known as "Phacops Crossleii." This has large eyes for its size, each one possessing about 76 facets ; it is a small Trilobite and does not bear spines like the Odontopleura. I notice this P. Crossleii was named after Mr R. Crossley, of Whitefield, Bowning, in recognition of assistance rendered by collecting specimens for identification.
The deposits on the Murrumbidgee, being Devonian, should also bear some good specimens, so that there is an opportunity for assistance from our friends out that way ; therefore I would ask them to keep their eyes open for fossil "Spiders," which is the name given to them by some of the uninitiated.
25 August - - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.X. DIATOMS. (By A.J. Shearsby).
The fossils which have been dealt with up to the present, are ones which are discernible with the unaided eye. To vary the monotony I am going to enter on a description of some fossils which are as far as their individual structure is concerned, invisible unless artificial means are employed. It seems almost incredible that you could hold a handful of them, consisting of many millions, and yet not be able to distinguish one! Such, however, is the case and the objects under treatment in this article, are known as "Diatoms." There are two samples of these organisms in the Mechanics, one of which is labelled "Tripolite," from Barraba, and the other "Diatomaceous earth," from Cooma. Each of these samples on being examined, looks very much like pipeclay or whitening; others are like flour to the touch. How different, however, is this Tripoli in structure - for pipeclay consists of amorphous powder - whilst the Tripoli or Diatom earth is made up of minute fossil remains so small that it is estimated that in a cubic inch of the earth there are about 41,000,000,000 skeletons. Were it not for the Microscope these would have passed unnoticed to the present day.
It will be as well to explain what Diatoms are before proceeding any farther. They are (for there are many species still in existence), a division of a minute form of vegetable life, of the order known as "Algae" or water weeds, of which the green slime found in stagnant water is an example. Diatoms are, however, able to secrete an external skeleton, which is in two symmetrical halves each known as a frustule. Differing from a coral whose skeleton is a carbonate of lime, the frustules of the Diatom are composed of silica or flint. The Diatomaceous earth then is composed of myriads of these siliceous skeletons, which have been heaped together by the death of minute vegetable life. Place a little of this earth under the microscope and what do we see: Thousands of perfectly formed objects many of which when properly examined, glisten like jewels. No wonder then, that they have been called by many observers "Nature's Jewels." There seems to be no end to the variety of forms which they assume, as they occur circular, triangular, oval, oblong, star-shaped, etc., and yet small as they are they present markings, or sculpturing, which seems almost beyond belief. These minute carvings - some of which on measurement range as low as a one hundred and thirty thousandth of an inch - are all perfect and symmetrical, so that when under a very high power microscope, they look like a geometrical design. They are of very ancient origin as their frustules are found in some Silurian deposits, and as before mentioned, they are still to be found living. The dark brown slime so common in ponds and creeks, on being placed under the microscope, will often be found to consist of living Diatoms.
These minute organisms may seem to many as not worth bothering about, but it will be found on giving them the attention they deserve, that small as they are, they have helped to build up vast tracts of our earth with their siliceous skeletons, made from the silica extracted from the water in which they flourished. Take for instance the great Andes Mountains in South America, which rise to the height of over 25,000 feet above the level of the sea. These, together with many other places which might be mentioned, have been proved to consist to a large extent of the skeletons of Diatoms. Coming nearer home, we find that large deposits of this Diatomaceous earth are to be found at Cooma, Barraba, Richmond River, and the Warrumbungle Mountains ; and I do not doubt that if some of the light, white earths in the Yass districts were examined, they would be found to consist of these minute fossils. It may be of interest to readers to know that this earth is used for many purposes. The explosive, Nitroclycerine, was discovered in 1847 by Sobrero, but being so very dangerous it was not till 1863 that Nobel made some practical use of it. He then mixed it with gunpowder,and used it in this state for blasting purposes. It was still, however, too dangerous for ordinary purposes, and it was not till 1867 that he fixed on the final stage by mixing it with Diatomaceous earth, which he found would take up no less than three times its weight of the explosive without becoming damp to the touch. This mixture, which is carefully prepared, forms that powerful explosive now known as dynamite. Diatomaceous earth when of a good quality has its particles in such a finely divided state, that it is used as a polishing powder, and under the name of Tripoli it is well known to many.
The most interesting feature about this earth is the fact that it is used in some parts of the world as food. In Europe it is known as Kieselguhr, and Bergmehl (mountain meal), and the peasants use it as a substitute when flour is scarce. They do not, as a rule, use it pure, but mix it with what flour they can obtain, and make bread of it. Needless to say they derive very little benefit from it, as the earth is nearly pure silica, although some samples are found with about three or four per cent of nutriment. It is perhaps fortunate that we have deposits of edible earth in this country, so if the present drought continues we will be able to fall back on this "Mountain Meal" should the price of flour become prohibitive! At any rate we would perhaps get as much nourishment from it, as we do now out of the substance which is sold as meat!
1 September - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.XI. ANCIENT AUSTRALIAN ANIMALS. (By A.J. Shearsby).
The number of dead wallabies and other marsupials to be found in the bush since this drought has been in possession of the land, together with the great demand for their skins, brings to one's mind the possibility of this distinctly Australian form of animal life becoming extinct in the early future. It seems strange that Australia and New Zealand should possess such a large number of these marsupials, whilst there is only one to be found outside these countries. This exception is the opossum, which is also found in a native stage in America. No marsupials are to be found in Europe at the present day, except, of course, those which have been imported from other countries. They existed, however, in ages long past, as their remains are to be found in the rocks of the Eocene period. Not only ins the present animal life peculiar to Australia, but we find on examining the fossil remains of pre-historic quadropeds that they also differed distinctly from those of other countries. Up to the present no remains have been found that would tend to show that animals similar to the tiger, elephant, ox, or sheep, ever existed in Australia, prior to the advent of the white races. The remains of animals which have from time to time been found in different parts of Australia, such as Wellington Caves, Darling Downs, the country round about Melbourne, and coming nearer Yass may be mentioned the Harden district, all show that the animals that were in existence prior to the present ones belonged to the marsupial or pouch-bearing family. It will be found also that these pre-historic animals were, as a rule, quite gigantic when compared with their descendants now living.
At Cunningham Creek, near Harden is be found a large deposit of bones, buried at a depth of about fifty feet. These were discovered when digging a shaft for gold, and were found lying immediately above the wash dirt. On being examined they proved to be the remains of a large marsupial, known as the "Diprotodon." According to Prof. Owen, the great authority on fossil remains, the Diprotodon was an animal of the marsupial family, which stood about eight feet in height. The tail was long and similar in shape to a kangaroo's. The skull was enormous, being three feet in length, and nearly the same measurement in height. The brain power was very small, as the face of the animal took up nearly all the available space. The front teeth -two above and two be low — are described as enormous, whilst the back grinders are six inches long. Naturally, having such a large head, the mouth would be proportionately large, though from the formation of the teeth it seems that the animal was vegetarian in its habits, and lived on leaves and small trees. Although the skull is similar to a kangaroo's, the Diprotodon differed from the modern animal in having very long fore-limbs, which seems to point to the fact of it walking on all fours. It will not be seen then from the above description that the Diprotodon was a very large animal, and as it did not jump like the kangaroo it has been compared to a pouched Rhinoceros. Another peculiarity about this monster was the short neck, which with the long fore-limbs made it impossible for the animal to eat grass unless by it went down on its knees, or posessed a long trunk like an elephant. It seems to have had no means of defence, and as remains of small skeletons have been found in caves inhabited by carnivorous animals, they were probably carried there by the flesh-eaters as food.
Living at the same time, and in the same of districts as the Diprotodon, was a similar animal called by Prof. Owen the "Nototherium." Like the former it was a vegetarian, and became extinct at the same time. Then there were the carnivorous flesh-eating animals. One of these seems to answer the description of the "Native Devil," and the other was an animal similar to the " Thylacine" or pouched dog. Both of these animals are extinct as far as the mainland is concerned, but their descendants are still to be found alive in Tasmania, which tends to prove that during that time Tasmania was united to the mainland. Still another carnivorous marsupial was in existence on the mainland during that period, and remains of it have been found in the caves.The skulls have very powerful jaws with an array of long sharp teeth or fangs. On account of these teeth and powerful jaws, Prof.Owen named it the "Thylacoleo" or pouched lion. It seem to the have been very fierce and preyed upon the smaller helpless animals which lived at the same time. Remains have also been found in the Darling Downs belonging to an extinct pouched ant-eating porcupine. It will be seen then that all these ancient animals belonged to the same family as the modern ones, namely the marsupials. Remains of many of the modern ones have also been found, together with the bones of wingless birds partaking of the nature of the emu. Some geologists suggest that the cause of the extinction of the Diprotodon was a sudden climatic change which overwhelmed the continent, and was not due to a universal deluge, as otherwise all the marsupials would become extinct, and Australia would have had at the present day, animals similar to those of other parts of the world.
4 September - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.XII. LIMESTONE CAVES. (By A.J. Shearsby).
Amongst the cables which appeared in the papers the other day, was the following item:— "London, Thursday 28.8.02. Recent blasting operations on the eastern side of Gibraltar have disclosed a cave 350 ft. long and 70 ft. high, the stalactites and stalagmites forming pillars from the roof and upon the floor." This draws the attention to one of the most interesting features in connection with the geology of the Yass district, that is, the series of beautiful limestone caves which are to be found near Taemas and Cavan, and at Weejasper. The rocks in which these caves are formed, will be found to consist of a hard, compact limestone, which looks almost indestructible. However, the great solvent of nature - water, leaves its mark on these hard rocks, for the exposed surface of the limestone is to be found covered with ridges, the edges of which are often as sharp as knife blades. These are caused by the action of rain water charged with Carbonic acid gas, abstracted from the air, falling on the limestone and dissolving the carbonate of lime and the resulting fissures which are known as grikes, in time are widened and deepened, until they sometimes extend considerable distances into the interior of the rock. It is on account of these deep grikes, that many rivers disappear into the earth and do not come to the surface again till some miles of underground country have been traversed. Then there is another way in which water has been admitted into the interior of these rocks. Volcanic disturbances have rent the limestones leaving large and tortuous cracks, into which have been turned streams large and small, which in many cases have a large quantity of Carbonic acid gas in solution. Exposed to the wear and tear of the stream and the solvent power possessed by the contained gas, the hard limestone has had to give way, and in course of time, what was once a mere crack or fissure, becomes a large wide channel. In many cases immense blocks of stone have been loosened by the action of water soaking through from the surface, and crashing down into the stream, which though it may be as clear as crystal, has the power to dissolve the obstructions and in the end is left a vaulted chamber which in some cases is hundreds of feet high, into which the light of day has never entered. Further disturbances of the earth's crust may raise the passages beyond the reach of the stream, or turn the course of the stream in another direction, and leave the cave dry enough to admit of exploration. The water after issuing from these caves will be found to be very "hard," from the amount of lime held in solution. Alteration of temperature and evaporation tends to precipitate a large quantity of the lime, the deposit being known as tufa or travertine.
I have noticed that some of the small streams that spring from the limestone hills just above the Taemas bridge, are so saturated with lime that leaves, ferns, and twigs that happen to fall into them near their source are speedily encrusted with the deposit so that they seem as if made of stone. These incrustations however must not be confounded with petrifactions, as the organic matter is not petrified or turned into stone, but only covered with the carbonate of lime. In some parts of the world this travertine is so compact and hard that it is used for building purposes, and as it makes a fine polish it is used in place of marble.
Returning to the cave it will be noticed that it differs in many ways to a cave hollowed out of sandstone. The sandstone cave consists generally of dark dreary looking vaults ; but what a different aspect the limestone cave presents when lighted up! Hanging from the roof are beautiful tapering shafts or stalactites of all sizes and thicknesses, from that of a needle to a column reaching from the roof to the floor of the cavern, and many feet in circumference. They range in color from a transparent and sparkling white, to various shades of yellow, pink, blue, brown and black. Festoons of curtains with colored stripes, and masses of sparkling wall decorations are to be seen on every side by the wondering and delighted visitor. Under foot the ground is in some places sand, and at others a formation similar to that found on the roof. Pillars from a few inches to many feet high called Stalagmites, rise to try and meet as it were the roof, and in many cases succeed with the help of the stelactite above. How are these strange and in many cases magnificent decorations formed? When the water charged with the carbonic acid gas soaks through the limestone by means of the fissures, it carries with it some of the lime held in solution. When it reaches the roof of the cave it hangs there for a while in drops. Whilst banging a change of temperature will probably cause some of the gas to escape, and the water not being able to retain all the lime gathered on its journey, has to deposit it on the roof of the cave. This action goes on year after year each drop depositing its little contribution, until a tube or stalactite is formed which in time is increased into a large column. As the drop is not always evaporated on the roof it has to fall to the ground when increased in bulk by fresh soakage. Should any lime be left in it when it falls, further evaporation causes it to deposit the contained mineral and so we have the beginning of the Stalagmite. Many experiments have been made so as to get an idea of the rate of growth of a stalactite. In the caves of Europe and America which have been under observation for about 200 years it has been estimated that it takes from 200 to 1000 years for a stalactitc to grow one foot. In the Jenolan (N.S.W.) caves a stalactite in sixteen years only grew three eights of an inch in length by one eighth of an inch thick, so that it must have been upwards of 300 years reaching its previous length of eight inches.
8 September - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.XIII. THE CAVES AT WEEJASPER (Continued.) (By A.J. Shearsby).
The Jenolan Caves near Tarana, have become famous all the world over on account of the number of tourists from foreign countries who have visited them. They are indeed worthy of all the praise the visitors shower upon them, as the magnificent fairy-like sights which are to be found buried in that district, have been rendered easy of access by the New South Wales Government, which has taken over the complete control of the caves. By this action of the Government, caves of surpassing beauty which were at one time almost inaccessible have been opened up in such a way, that even the lady tourists have nothing to complain of. Steps have been cut into the solid rock, bridges have been erected over deep fissures and underground streams, and guides are supplied who conduct visitors, and point out the beauty spots of each cave. To stop vandalism in the way of breaking the stalactites etc., and generally disfiguring the caves with names, also to prevent people from getting lost in the vast number of galleries which pierce the rocks in every direction, the entrances of the caves are closed by means of iron railings and gates. Sights such as those to be seen at Jenolan are well worth the trouble of travelling hundreds of miles to see, but the residents of Yass district have no need to go such a journey, when there are within a comparatively short distance caves which, though they may not in their present state of development be as magnificent as the well developed Jenolan Caves, still they will leave impressions on the visitors' minds, which will bring forth pleasant recollections in years to come. These caves are situated at Cave Valley, near Weejasper, about 33 miles from Yass. It may seem a long journey to some who require all the nice things to be close to their threshold, but they overlook the splendid changes of scenery to be met with on the trip. Crossing the Murrumbidgee River by means of the Taemas Bridge, our way is by the road which wends itself up over the limestone hills, and when the climb brings us to the top of the ridge, we are rewarded with a splendid view of the valley of the Murrumbidgee.
The road continues to take us over hilly country, giving occasional glimpses of Downing Hill in the distance. When about 28 miles have been covered the road begins to drop rapidly, and we soon find ourselves closely hugging the hillsides, until at last we come in sight of the Little River which even in the driest times courses rapidly through its beautiful fertile valley, hurrying onwards to join the Murrumbidgee. The road crosses the river at the foot of the hill by a very substantial bridge, and continues on its way to Tumut. We will now leave the main road as the caves we intend to visit are lower down the valley. Turning to our right, we pass the Police Barracks and follow the track which runs through a rich looking flat, on which many cattle are to be seen peacefully grazing. Through sundry gates, into rougher country where blocks of limestone scored with grikes are to be found jutting up in all directions. All around us in this party are to be seen the effects of the bush fires which swept through last summer. In many places the hard limestone was subjected to such an intense heat that it has been turned into lime. The country here seems to be honeycombed with caves, which would no doubt open out well if properly investigated. When about three miles from the bridge, the track turns to the left and it is time that we had our torches or candles ready to light us into the dark places of the earth.
On the side of a little rise consisting of a regular jumble of limestone masses, an opening is found, roughly speaking, four or five feet in diameter — not too inviting to the beginner, as all is dark and quiet beyond. Into it we must go, however, for after our long journey we want to see the sights. Lighting our candles, a start is made by crawling through an awkward hole which takes us down below into a cave, which, when well lighted up, especially with a magnesium lamp, in itself almost repays the visitors for the trouble of the journey. Hanging from the roof are some exquisite stalactites which sparkle in the rays of light thrown on them, while directly in front is a very large stalagmite which has struggled for many years to reach the roof of the cave. In fact thousands of years would not be going too far in estimating the age of it, when comparing it with examples of the rate of growth quoted in the last notes, for this stalagmite is about eight feet high and three feet in diameter, and carved and sculptured as only nature can design and execute such work. Behind it hangs a large stalactite and adjoining it is what might be termed a petrified waterfall. Leaving this chamber are several passages, each of which leads to fresh wonders. At times we enter large and lofty places reminding one of Aladdin's jewel cave, and often we find ourselves crawling along low narrow tunnels all of which were once the channels of the underground rivers. Hour after hour can be spent in walking about in these caves, enjoying the variety of natural decorations. In one chamber, festoons of shawl-like drapery hang in artistic folds, and when the magnesium light is thrown on, they sparkle as though covered with diamonds. Many of these shawls are ribbed with different colors similar to an artificial shawl and some of them — the thin ones — show the colored stripes very strongly, when a light is placed behind them. These shawls are caused by the water charged with limestone, evaporating as it runs or trickles down the sloping roof of the cave, and depositing the material along its route. At times the water, besides taking up the carbonate of lime, will also be charged with iron or some other mineral, so that the deposits of lime will be stained, hence the regular bands of various colors. (To be continued.) 4 '9 02.
18 September - A.J. Shearsby, XIV - The Caves at Weejasper (Continued), Yass Evening Tribune:
Notes on Geology. No.XIV. THE CAVES AT WEEJASPER (Continued.) (By A.J. Shearsby).
Turning from the shawls, we find in another chamber, a large formation which cannot be compared to anything but a petrified waterfall. Much larger than the one noticed near the entrance, it falls from a good height in graceful folds of a dazzling whiteness. Here is the result of a large stream of mineral water, which flowing through some crevice, has been compelled to form a lasting monument of its past activity. Through another winding tunnel and we enter more caves, one of which has its roof crowded with stalactites and packed as close as possible without touching each other. The fine white color and delicate shapes of these dazzle the eyes when the magnesium light is thrown on. The place is like a fairy land and we feel lothe to leave, but time flies and we have a lot to see before we can return to the sunlight again.
In caves where the roof is studded with stalactites like these, care must be taken that no guns are fired off; as the shock is liable to loosen many of the heavy stalactites and cause serious accidents. It is not often that the stalactites and stalagmites are met with joined together in an unbroken column, but several examples, some of them very beautiful, are to be found here in these caves. Another passage leads us into a chamber which contains little grottos with their delicate snow-white stalactites hanging down like the bars of a cage, through which we notice that the walls and floors are adorned with crystals. Some of these grottos remind one of similar formations in the Jenolan caves, but alas! how they have been defaced by thoughtless visitors, who will persist in breaking and carrying away the most effective pieces, only to throw them on one side, when they see how common-place they look when exposed to the light of day. There seems to be no end of tunnels penetrating this limestone mass, and many of them are worn smooth and polished by the traffic of myriads of animals which have been in the habit of passing in and out for thousands of years. Here and there we find heaps of bones of extinct marsupials. These bones when cemented into a hard mass with earth and carbonate of lime, form what is known as "Bone breccia."
The tourist will find that these caves are nice and clean, that is, there are no running streams to make the place sloppy, and they would if a little money were expended on them, prove to be a very attractive holiday resort. It is a great pity that many of the best formations are completely ruined, by people — who ought to know better — writing their names or initials in far from attractive letters on the walls, stalactites, etc., and even, as mentioned before, breaking pieces off. A trip to the eaves is most enjoyable, and should be indulged in by all who can afford the time to go ; but to advertise the event in such a vandalistic manner as leaving ugly initials scrawled or smoked on some of nature's prettiest handiwork, is carrying things a bit too far. Considering the state that some of the caves have been left in by some visitors, it is no wonder that Mr. John Carey on whose property the caves are, prohibits trespassing, but I know he is only too willing to allow people to inspect, on condition that no damage is done by them.
It is time that we returned to the bright sunlight above us; so retracing our steps and getting glimpses of other little nooks which time will not permit us to examine closely, we reach the entrance, well satisfied with the result of our hurried inspection. The glare and heat of the sun seems to be intensified after issuing from the cool grottos, and we wend our way among the hot limestone blocks and a few hundred yards away come across another cave with a large and lofty entrance. Although the means of access to this cave are easier, it will be found that as far as it has been opened up, it is not nearly so attractive as the one we have just left. There are needless to say, many pretty formations, and an hour or two can be spent with advantage in rambling about; and there is no doubt that by carefully sounding the walls and floors, and judiciously using a pick, in the likely spots, caves would be discovered opening off the main chambers, which would equal the others, with the additional advantage that they have not been disfigured by thoughtless visitors. But it is getting late and we must make tracks for our camping place for the night as there are other caves higher up the river which are worth the journey to inspect, and they will take all the next morning. Although the entrance or vestibule of the cave we are just leaving seems to have been used many times for a camping place, as it is so sheltered and roomy, a more pleasant spot will be found near the river banks where a plentiful supply, of water is at hand. Retracing our steps through the sharp edged limestone blocks, we reach the main track, and about a mile below the bridge we find a cosy nook near a pretty bend of the Little River where we will pass the night. Here among the tall oaks and the bracken, which thickly line the banks of the swift clear stream, we have our evening meal, washed down by the refreshing billy tea, watching the while the glorious sunset effects, as the orb of day sinks slowly behind the purple hills. Gradually the light fails, and the landscape is obscured by the ever increasing gloom, and by the light of the stars we turn in, tired out it is true, but well satisfied with what we have seen during our day's ramble. (To be continued.) 10/9/02.
25 September - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.XV. THE CAVES AT WEEJASPER (Continued.) (By A.J. Shearsby).
Morning comes and those who are fond of a good refreshing cold bath will find their desire gratified in the stream close by. The water is so clear, that you are liable to be mistaken in the depth, and stepping into what looks a shallow hole, find it is many feet deep. However, a good splash round in cold water is a grand appetiser, so that when it is ready, breakfast soon disappears. On leaving our camping ground, we make towards the bridge and crossing it, turn to our right and follow the path towards Coodra Vale house, the residence of Mr J.T. Jones, which nestles in the shade of numerous tall acacia, oak, and willow trees, close to the river bank. From this spot a splendid view can be had of the Little River valley, flanked as it is by the mountains on either side. These together with the tall poplar trees and flats with browsing cattle, help to make a picture which would when reproduced on canvas, be hard to excel. Passing on we find a few hundred yards higher up the river, what one would little expect to see in these parts, that is, a "home made" suspension bridge. On either side of the river platforms have been built up among the branches of the oak trees, over which have been passed steel cables, which are tightened when required by means of a windlass. Battens have been fastened down across these cables, and the flooring completed by means of stout sheets of bark. Hand rails are provided in the shape of more wires thrown across tile river at a convenient height and connected with the main bridge, the whole work forming a very creditable piece of engineering, of which the constructors may be justly proud. Our way lies across this gently swaying bridge, from which we see on the other side of the river, vignetted by the overhanging boughs of the trees which now surround us. the residence of Mr. A.H. McBean. We cannot help pausing for a few moments on our perch up among the branches to admire our surroundings. Underneath runs the river, branches of trees surround us on each side, and hide the sky above, while in front large masses of bracken hide the foreground. A little farther away are the white cottages peeping out amongst the poplars and fruit trees, with a background of steep hills to add to the beauty of the scene. However, we are bound for the caves and must proceed.
Crossing the flat,we meet the Tumut road, and following it for a mile or so find it bends to the right on its way over the mountains to Tumut. Our path is now to the left of the bend, and about a hundred yards from the road, we come to the entrance of the caves known as the Punchbowl caves. Lighting our candles we enter, and after our eyes are accustomed to the dim artificial light, we have a look around us. The first peculiarity which strikes the visitor is the deep gloom as compared with the caves lower down the river. The cause of this appears to be the absence of the light colored lime encrustations on the walls and roof, which in this cave are of a dark brown tint. Proceeding on our inspection we come across a low part of the cavern where the roof is supported by a number of thick stalactites which have succeeded in joining company with their respective stalagmites. These formations look all the more brilliant on account of the gloomy surroundings, although the hideous initials scattered about do not tend to improve the view. Whilst engaged in examining this cave in which are to be found many little nooks of exceeding interest, we were startled with whirring and flapping noises in the air around us, and suddenly our lights were extinguished and we were left in pitchy darkness. It seems that we have disturbed a colony of bats which have made the cave their home, and startled with the noise and lights, they have dashed at the latter and put them out. To those of a nervous disposition who have not been plunged into total darkness like this before, it is an awe inspiring sensation to be thus attacked. Here in the thick impenetrable darkness many yards away from the surface of the ground, with dangerous pitfalls lurking in the floor, making it impossible to roam with safety without a light, it is small wonder that matches are eagerly sought for to re-light the candles, and now being forewarned more care is taken to shield them from further mishap.
We soon arrive at the formation known as the Devil's Punchbowl, from which the cave receives its name. This consists of a series of semicircular shallow basins, which in wet seasons are filled to overflowing with water. They are arranged in the form of steps or terraces, so that the water in the top ones overflow into the basins beneath. This formation reminds one of the beautiful Pink and White Terraces of New Zealand, before they were destroyed by the earthquakes. The season being very dry these punchbowls are empty, but the inner surfaces are found to be encrusted with crystals which glitter like jewels when a light is moved near them. Another very attractive feature of these caves is that several of the openings connecting the chambers have stalactites on each side, forming artistic doorposts. Delicate filigree-like work hangs from the roof in many places, and curtain-shaped deposits are to be found as in the other caves. In one cave a splendid large pillar shows signs of either an earthquake or a subsidence, as it has been broken away at the upper end from the roof. Examination shows that many years have passed since the rupture, as the break has been already well coated with deposits of lime. In various places the floors of this series of caves sound hollow so that there is every possibility of fresh caves being opened up by those interested, especially as the surrounding limestone country proves on inspection to be pierced by many long tunnels, which for want of time we are unable to investigate thoroughly.
Regret is expressed by all the party that we have to leave this beautiful district, without further cave hunting, a feeling which no doubt will be common to all tourists who take the opportunity of visiting the caves in the Weejasper county. Many people may think that the Hurried descriptions of the caves are exaggerated, but it will be found that words cannot express the magnificence which the eyes see in these underground chambers of nature's handiwork. More caves, some of which are of an immense size, are to be found in the Cavan district nearer Yass; these also will be described in a future article.
2 October - A.J. Shearsby, Yass Evening Tribune:
Notes on Geology. No.XVI. CAVES EXPLORATION. By A.J. Shearsby.
Although cave-hunting is a very interesting and enjoyable occupation for leisure hours, it must be borne in mind that at times it has its dangers, which are all the more to be guarded against in consequence of their being invisible ones. In newly opened caves you do not know if the over-hanging rock is solid and firm ; if not, the slightest shock is liable to send a mass of many tons crashing to the ground, and perhaps even if no bodily injury is sustained by the explorer, his path to the open air is cut off by the dislodged mass. At other times the floor of the cave will seem to offer no obstruction, as it looks so level and clean, but in many places it may be only an inch thick or even less than that, and the unsuspecting wanderer finds himself falling through into a cavern, maybe hundreds of feet deep. Even worse than the above, is the carbonic acid gas which collects in some limestone caves. This gas, which as mentioned previously is held in solution by the water which soaks into the caves, is released at the water evaporates. Should the cave not be well ventilated the gas being heavier than the air sinks to the bottom and keeps on collecting until in some instances the cave is filled with it. Any person entering the cave, would be rendered senseless almost immediately after breathing the carbonic acid gas, or choke damp as it is sometimes called. In many instances, however, this gas is only found in close proximity to the floor, as there may be a small supply of fresh air which gains access to the cave. An illustration of this kind of cave is the famous Grotto del Cane, or Dog's Grotto, a small cave near Naples in Italy. No serious effect is perceptible by a person entering and standing up, but if a dog or other small animal is introduced, it immediately falls down senseless, and if not taken out to the fresh air it would die. The reason of this is that the gas has collected and covered the floor of the cave like a stream of water, but it is not deep enough to reach the respiratory organs of human beings, unless they stooped or lay down in it. This cave was well known to the ancients, as it was described by Pliny, who was afterwards suffocated by poisonous gases at the great eruption of Vesuvius in the year 79.That the danger of poisonous gas is not foreign to the Yass caves, will be seen by the description of a cavern or fissure given below.
On the crown of one of Murrumbidgee hills between Good Hope and Taemas, on the road to Mr. Humphries' place, there is to be seen a few yards from the track a funnel-shaped depression in the ground known locally I believe as the Cat Hole, on account of it having once been the resort of wild cats. The diameter of this depression is about thirty feet, the sides sloping gradually, similar to a funnel, and end in a tunnel, at the entrance of which is an ancient peach tree, stated by old residents to be upwards of forty years old. Now all kinds of reports had reached me about this hole and each person had a different tale to tell concerning it. One report stated that the hole went straight down into the bowels of the earth, and nobody had been able to bottom it. Another stated that you could hear water rushing along the bottom; but most of the tales agreed with the statement that if you cast a stone down and waited long enough you would hear the stone strike the bottom, seemingly many hundreds of feet below. Not finding anyone who had actually tested these statements, my curiosity was aroused, and I determined to investigate at the first opportunity.
A party of half-a-dozen was formed, and we went well prepared with over 300 feet of rope and tackle, and a good quantity of candles and magnesium wire. Taking it for granted that the hole was perpendicular, a strong sapling was felled to put across the fissure to carry the ropes and tackle. However, when the scene of our operations was reached, we found that instead of running straight down into the earth, the opening proved to be a tunnel with a moderately steep slope, so that we would have to wait many a long year before a stone thrown in here would reach the bottom of the hole. Into this tunnel we proceeded with our candles and lamp, which latter was well protected, in case of draughts and bats, by thick glass sides. We had not descended far before we became aware of the atmosphere being uncomfortably warm and oppressive, which was a very bad sign to start with. After scrambling along for a short distance we found our way barred by a deep fissure about four or five feet wide crossing our path, further progress being impossible on the other side by the wall of the cave which rose perpendicularly. Here perhaps was the bottomless pit so often spoken about! The lantern was lowered at the end of a cord to see the way and test the air, and as it rested on a small ledge about thirty feet below, the chasm was bridged with the sapling, and with the aid of a rope I descended. Reaching the ledge the lantern was again lowered, and at about fifty feet it rested on what appeared to be the floor of the fissure.
On arriving at this landing place and all being safe, more of the party descended and had a look around. It was found that the passage inclined downwards for some distant, and like the tunnel above us, ended in a perpendicular fissure, but only three feet wide, the walls of which consisted of a solid encrinital limestone, with an odd coral or two showing here and there. The ropes were again brought into use here, and landing on the platform below, this was also found to slope downwards, and like the others ended with a figure. The air had now become very unpleasant and rather thick. The cause of this was put down to the large quantity of vegetable and animal refuse, which had been washed down from the river. So far this place as a cave was very uninteresting, as no formations in the shape of stalactites common to limestone caves had been discovered. We were still in hopes of finding at a lower level a chamber which would repay us for the trouble in clambering so far down. To be continued.
6 October - A.J. Shearsby, Caves, Yass Evening Tribune:
Notes on Geology. No.XVII. CAVES EXPLORATION (Continued). By A.J. Shearsby.
The next shaft was more difficult to negotiate, as it was very narrow and the sides were rough and jagged. At the bottom a sloping passage similar to the ones above, but narrower, and toward the lower end steeper, till it was blocked by a large mass of limestone, which had fallen from the roof, and was probably no means of preventing the fissure from closing. Climbing over this block, we found that the continuation consisted of a narrow crack running down into the earth, was barely eighteen inches wide, but rope was brought to allow one of ihe party to explore. Before attempting to enter this narrow passage, however, the lantern as usual was lowered to test the air and light the way. When down about thirty feet, it rested on a ledge and gradually died out. Thinking the candle wanted replenishing, it was hauled up, but finding there was any amount, it was re-lighted and lowered the second time, only to be extinguished as at first. This occurred four times in succession, showing that it was extinguished either by wind or carbonic acid gas. As the lantern was practically draught proof, and the air in this part of the cave was so still and close, it was unlikely that the cause was a strong draught of air such as is sometimes met with in caves. It could therefore be nothing else than the deadly carbonic acid gas, which had filled the lower part of the fissure, and prevented any further examination. This was the first experience of the other members of the party with such a case. They all came down and witnessed the way in which the light died out as it came in contact with the gas. Had not the precaution been taken of lowering the light into these shafts before entering them, the result would have been very serious, as unconsciousness and death would have overtaken the unsuspecting intruder, before help could have been rendered.
The narrowness of the shaft this place would have presented many difficulties, and seriously hampered any attempt at rescue. As the air had by this time become more unpleasant to breathe, and the smoke from the candles and magnesium light hung around in a heavy looking mass, it was unanimously decided to retrace our steps and reach the fresh air. The depth reached was about 200 feet, so that the fissure probably extended a great distance below where we were checked. As to the gas in the lower portion, there is a possibility of it rising and falling as opportunity offered, in the way of the opening or closing of crack communicating with fresh air, so that future inspection may find the gas at a lower level. The whole series of shafts and tunnels seem to me to be the result of a comparatively modern earthquake, which has rent the limestone, forming what is known as a "fault," and falling boulders have prevented the opening from closing again. The gas derived from the decaying organic matter which has been washed down at each heavy fall of rain, assisted by that which was held in solution by the water, has then collected and filled up the lower crevices.
I cannot recommend this place as a sight worth seeing, as there are no nice formations like those fouud in the caves I have referred to before, and I have only mentioned it as a local illustration of one of the dangers attendant on cave-hunting. A good day can be spent about the hills in this part, for here and there are to be found nice little caves which only need the rubbish to be cleared away from the entrance to show some very pretty stalactites which have perhaps not been disturbed for centuries. A rope lowered into one of these holes led the way into a chamber about twelve feet in diameter which had seemingly never been disturbed before except by some sheep and rabbits which had fallen in and could not escape for their bones were found scattered on the floor. We could not expect to find much in a small cave like this, but what there was, was in a good state of preservation and well worth seeing.
A Walk along the crest of the hill was rewarded with a very extensive view of the Murrumbidgee district. Down the river to our right lay Good Hope, while to the left, up the river, could be seen Taemas house, and a few miles beyond, the Taemas bridge. The road crossing the bridge can be traced for some miles on its winding course to Weejasper. The district all round here is well known to Yassites, as it abounds in their favorite picnic resorts, and is within an easy distance of town. How many of the visitors to the Murrumbidgee, however, have thought of the ages which have passed since what is now hard rock, was a world of life? The rocks here belong to the "Devonian" system, and contain the remains of the marine life which existed at that period. In England and Scotland this series is represented not only by the marine deposits, but also by thick layers of sandstones which contain a large quantity of fossils belonging to the land and fresh water, and are therefore believed to be lake deposits. This formation is known as the "Old Red Sandstone." It was during this period that the terrestrial vegetation became very abundant, and the marine fish also increased. These rocks are also noted on account of recording the first traces of fresh water fishes. The Crinoids, which have helped in a large way to build up the limestones, are shown in Murrumbidgee rocks to have been of a much larger size than those of Hatton's Corner, which belong, of course, to a more ancient period. There are also remains of the ancient fishes to he found near Good Hope, in the shape of the bony plates with which they were covered. It will be noticed by many that large masses of limestone are composed almost entirely of shells which seem to have grown very abundantly in those times. The majority of them which are peculiar to the Yass deposits — not having been noticed elsewhere — belong to the Spirifera variety, and are known as "Spirifera Yassensis."
20 October - A.J. Shearsby, XIX - Granite (Continued), Yass Evening Tribune:
Notes on Geology. No.XIII. GRANITE. (Continued). (BY A.J. Shearsby).
I wonder how many of the active Yassites have ever thought it worth their while to take a walk down the river from the bridge to Hatton's Corner ? It may not seem an attractive walk to some who take it for granted that it is the same river all the way ; so, why need they bother themselves by following it? Still many could make the trip most enjoyable, especially if they will only combine a little nature study with their ramble. I remember the first walk I ventured on in that direction, was not too pleasant, as I got tangled up with an almost impenetrable thicket of briars, which like the lawyers, receive you with open arms, but make it very hard for you to get out of their clutches again. However the briars can easily be avoided now, for through the drought the river bed is easily accessible in many places to the foot passenger. Other signs of the drought are to be noticed around us, besides the miserable stream of water which trickles along, for the once luxuriant willows have been lopped and hacked about to keep the stock alive. Even the 'iron horse' has been the means of altering the look of the river, for here and there channels have been cut and blasted out of the solid rock, so as to drain the pools higher up the river, and fill the water hole from which the water supply is pumped for railway purposes. It is to be regretted that there is not a suitable place to build a weir some distance below the bridge, for even if the water was contaminated and made unfit for human consumption, the resulting stretch of water would go a long way to make the environs of the town much more attractive.
The rock in which the channels have been cut is found in many places to be of a decided green color, due very likely to the presence of "glauconite" or silicate of iron. Passing the pumping station we soon reach the wool-scouring works, which possess even in these dry times a very nice water frontage. At these works the greasy wool and filthy looking locks are treated to a well-deserved bath, and issue from it nice and clean and more business like. The water, if you can call the fluid that comes off water, is run through a large filtering bed erected on the bank of the river, and returns to the main stream as clear as crystal, and according to some, purer than when it was pumped out of the river.
Leaving the wool-scourings behind, we continue our walk and follow the river, which, after this point will be found to alter in a marked degree. The rocks passed over up to this point consisted mainly of comparatively soft micaceous sandstones and limestone, but here the bed of tile river is found to be crossed by blocks of hard compact rock which stretch across the river, and disappear into the banks on either side. Breaking a piece off we find it to be granite. Now, quite recently I was informed by some people who are supposed to know, that there was no true granite near Yass. This surprised me as I had often, lower down the river found small water worn blocks of it. No doubt the trouble arose through my informants basing their belief on an examination of the rocky country just above the Yass bridge. The cliffs near the Police Barracks are certainly not composed of granite, but consist of what is known as "Porphyrite." It seems strange that these old residents had not extended their investigations a few miles lower down the river, for there they would have found enough granite of various colors to build half a dozen federal cities.
Taking the piece which was broken off, the student will naturally wish to know how to recognise granite in future. Well, it will be found that the specimen obtained is composed of three different colored minerals — a pink, a black, and a glassy looking material which binds the other two into a hard, solid mass. The broken surface of the stone shows the black material to be in the form of plates generally hexagonal or six-sided, and on using the blade of a pen knife it will be found that the plates are soft and split easily, that in good specimen, one plate can be divided into perhaps a dozen thinner leaves, each one preserving the hexagonal shape of the original. These black plates are known as "Mica." The pink pieces we are just able to scratch with the knife, and when they are broken they always show flat, shining surfaces. These are crystals of "Felspar." Now try the knife on the glassy cementing mineral, and it will be found that no impression can be made, as it is too hard. This is known as "Quartz." Unlike the Felspar and Mica, the Quartz does not break into plates, but always shows a rough surface when broken. This examination then shows us that granite is composed of crystals of Felspar and Mica, embedded in a matrix of quartz. We must not go away with the idea however, that granite is always made from the same coloured materials, as even in the Yass granites the colour varies. One large band of rock proves to be grey, another a cream colour, whilst not far off are some chocolate and bluish granites. In these the felspar will be of a different color, but in all cases it can easily be picked out by means of the blade of a penknife. In the Yass granites as far as I have found them the mica is in black plates, and is known as "biotile" or magnesian mica. Other samples contain white scales of mica, which are known as "muscovite" or potash mica. The mica in granite is sometimes replaced by "Hornblende " and it is then known as hornblendic granite. It can be distinguished from mica as it is harder, more brittle, and does not split into thin scales and it differs from the felspar in being softer. Porphyritic granite is a specimen which has very large crystals of felspar imbedded in the matrix, in some cases these crystals being found about a foot in length. (To be continued).
23 October - A.J. Shearsby, XIX - Granite (Continued), Yass Evening Tribune:
Notes on Geology. No.XIX. GRANITE. (Continued). (BY A.J. Shearsby).
Here then we have in close proximity to the town a most valuable building stone in the form of granite beds, and a little further out, we find the Coolalie marble deposits. What splendid buildings could be erected with these two local products! The granite forms an immense intrusive mass, which crosses the river and extends from the wool-scouring works to about a mile and a half down the river. The whole character of the scenery is changed with it, and to follow the bed of the river all the way, means a rough, difficult walk, the tramp taking you over the immense boulders, and bars of smooth, hard rock. Occasionally a break will be met with, and a beautiful pool of water will relieve the monotony. Picnic parties might well visit these spots, as the rugged hills through which the river finds its way make the places very picturesque. The waterholes are succeeded by more granite bars, broken in places, through which when in flood the river rushes in a foaming torrent. Should ever the builder find use for the Yass granite, he will have no difficulty as far as color is concerned for in this scramble extending over a mile, we find a large variety of colors. These include cream, light and dark grays, chocolate, pink and gray, and a pink inclining to a red. These when polished ought to satisfy the most exacting. Besides being of great value as a most durable building stone, granite is of great value to the mineralogist, on account of the cavities which are often found in the rock. On coming across one of these, it will be found as a rule covered internally with a mass of beautiful crystals ; the separate minerals - felspar, mica, and quartz - of which the granite is composed, having been deposited in their respective crystalline forms, instead of being jumbled together as in the surrounding rock, not only is this accomplished, but rarer constituents of granite are sometimes found crystallised in these cavities. Some of these are precious stones viz. the emerald, beryl, topaz and garnet. It will therefore be seen that a ramble amongst granite rocks may sometimes turn out very profitable, especially if a nice sized emerald was found in one of these little pockets, the best emeralds exceeding in value that of diamonds.
Hard as granite is, water in conjunction with carbonic acid gas and mineral salts, attacks it and causes it to crumble away. Here again valuable mineral is formed, for the potash in the felspar is removed, and the result is a fine white powder which is washed out and deposited elsewhere. This white powder derived from the decomposition of granite, is known as 'kaolin' or chimeny clay, and ias it is used in the manufacture of the finest kinds of china, a good deposit of kaolin would be of some value. On computing granite with limestone, a gieat difference will be found, as the limestone, as mentioned in previous notes, is to a large extent composed of animal remains, and being deposited in water is known as a sedimentaiy rock. The granite differs in showing no signs of organic remains, but is composed of hard materials welded together by the aid of heat, and forms one of the igneous rocks.
The igneous rocks are divided into two distinct kinds, the Plutonic, or those which have cooled and solidifird at a great depth and pressure ; and the Volcanic, those which have cooled at the surface of the earth. It will be found that plutonic rocks, of which granite and porphyiite are examples, show a coarse crystalline structure ; while the volcanic rocks are very fine grained and in some instances glassy. Examples of the latter class are the lavas, basalt, and trachyte. Ordinary glass being quickly cooled, is a good artificial example of the structure of volcanic rock. If, however, when in a molten slate, the glass is subjected to a great pressure, and only allowed to cool very slowly, it would show when solidilied, distinct crystals similar to a plulonic rock. Some of the lavas will be found to be honeycombed with holes and are known as vesicular lava. These holes are caused by tlie expansion of the steam generated by the contained water, and the rock is cooled before the openings can close again. Vesicular lava is common at the Canoblas at Orange. In other lavas the steam escapes whilst the rock is in a molten state, the openings close, and the rock when cold is then solid and compact. On grinding down a thin slice of granite for microscopic examination, the quartz matrix is often very interesting. Scattered through the apparently perfectly clear quartz, are innumerable minute vesicles of water. These vesicles show that the granite was formed under great pressure, for being unable lo expand and escape, the water was so compressed that it had to form the minute little cavities inside the quartz when it was solidifying.
The granite then being formed many thousands of feet below the surface, must have been foiced through the solid crust of the earth and now lies exposed in bosses and veins ; the surrounding rocks being often altered by llie pressure and heat, and in many instances, carried away by the action of water andthe atmosphere, leaving the vast masses of granite standing out to form, in many parts of the world, great chains of mountains. Locally the granite extends down the river, till it nearly reaches Hatton's Corner, when it disappears from sight, and its place is taken by a dyke of basalt, which crosses the river, and runs under the big limestone cliff just above the big waterliole at Bowspring crossing place. As the basalt forms one of the volcanic rocks it will be mentioned later on when the signs of ancient volcanic activity near Yass are brought under notice.
1903
8 June 1903, Yass Evening Tribune:
Notes on Geology. No.XX. Yass Sponges. By A.J. Shearsby.
When I say that Sponges are to be found in Yass, many will say: "Of course, you can obtain any quantity at the stores." Just so, but it is not to the ordinary toilet sponges, which for the greater part have been brought from places like the Mediterranean Sea, or the West Indies, and which were alive a few years ago; it is not to these that I refer, but it is to the sponges that spent their lives millions of years long past, in a vast and beautiful coral sea, since dried up, and subjected to many changes, and upon the bed of which is now built the town of Yass. Who would imagine, on looking round, that such things as Sponges could be picked up close to the town! Yet, in an afternoon's ramble at Nation's Corner, if you only know the exact spot, many of the remains of the Sponges that flourished in the Silurian seas will be found. Many people, on holding a piece of toilet sponge in their hands, would hardly believe that such a soft, frail-looking substance could be preserved for such an immense period of time, such as has passed since the Silurian Sponges lived. This doubt will be greatly shaken and probably removal altogether when it is pointed out that some species of Sponges have interwoven in their meshes an almost indestructible material known as silica or flint. Have you ever, on taking up a sponge, wondered what the soft elastic thing was when it was alive? We all know that the household sponge is a skeleton, the fleshy part having been removed in preparing the article for market purposes. It, however, does not help us much as to its life history. It is not long since even the most learned naturalists looked upon the sponge as a vegetable growth, and classed it with the sea weeds. To see a live sponge in an acquarium or in the pools of water at the seaside, one is not surprised at it being mistaken for a vegetable, for it generally appears as a slimy, greenish growth, attached to rocks or stems of seawrack, and looks very much like a thick, stunted form of sea-weed. In spite of appearances, however, the sponge is a true animal, and forms a most interesting object of study to those who are fond of biology. As mentioned above, the sponge has a skeleton which, when cleansed, forms the article of commerce. This skeleton is of a horny, a siliceous or flinty, or a calcareous nature, and sometimes a combination of the three. The internal matter is generally deposed throughout the framework, in the term of minute spikes, needles, or stars of flint or lime, and serve to strengthen the main skeleton. Around this skeleton is enveloped during life a slimy semi-transparent substance, which forms the flesh of the animal. This substance is practically structureless, and can be best described as being similiar in composition and appearance to the "Amoeba," one of the lowest forms of life with which science is acquainted. If a small piece of living sponge is examined in sea-water under the microscope, it will be noticed that the water is agitated in a most energetic manner. This movement is made more evident, and the direction of the currents is more marked if a little fine carmine powder is added. The reason of this movement is soon discovered. On close observation it will be noticed that the sponge is pierced with innumerable holes or canals, the majority of which are very minute, but here and there are to be found larger openings. These openings, it may be mentioned, correspond to the large and small openings to be seen in the toilet sponge. Watching the small particles of carmine, it will be seen that the water is drawn in through the small openings, and after traversing the internal channels of the sponge, it is expelled through the large canals. This is the way the sponge obtains its form, drawing in with the currents of water minute particles of matter, of which suitable parts are retained and absorbed into the system, and the remainder is voided with the outgoing current. This circulation is kept up by means of a series of tiny chambers which are lined with minute threads or "cilia," which keep up a continuous lashing motion in the one direction, the result being that the water is drawn in through certain openings and expelled though others. These cilia are similar in structure and action to the cilia which line the trachea and bronchial tubes of the higher animals, and prevent by the same lashing action, the accumulation of a large quantity of mucous or foreign mailer, which would otherwise block the passages which they line. It seems strange that we should find in one of the lowest forms of life (for sponges rank below corals in organisation), a structure which is so essential to the well-being of the members of the highest forms of animal life. I have before me a section of a sponge gathered at Rose Bay, Sydney. Under the microscope are to be seen the network of horny fibres, and intermingled with the fibres are small needle shaped rods; these rods are the spicules which strengthen the "skeleton." Under certain conditions the horny parts of the sponge are dissolved away, but the spicules are left intact, and are often found in large quantities in the mud or ooze, dredged from the bottom of the sea. These sponge spicules are also found in many of the oldest geological formations, and it is by means of their power of resisting decay that we are able to say that the sponge has a very ancient lineage. How proud people are if they can only show a genealogical tree by which they can trace ancestors back a few hundred years. Yet the toilet sponge has good reason to be prouder than they, for what mighty personage can be found, who can trace back a lineage of a million years? Yes, the poor despised but useful sponge, can claim ancestors hundreds of millions of years ago, for there in those Silurian shales at Yass are to be found specimens in a fair state of preservation. It is on account of the tell-tale spicules mentioned before, that the sponges have been traced in the Yass deposits, for to the ordinary observer a fossil sponge appears to be only a nodule of hard compact limestone; but the application of a magnifying glass reveals the minute spicules which in the specimens I have obtained are of a calcareous nature. Some of these sponges are to be seen in the case at the Mechanics Institute, and form another series of most interesting specimens of ancient life, peculiar to the Yass district, and will probably prove to be new to science, having only within the last year been brought to light.
1904
A.J. Shearsby, On a new species of fossiliferous Rhizophyllum from the Upper Silurian rocks of Yass, N.S.W., Proceedings of the Linnean Society of New South Wales, 30 November 1904, XXIX, Part 4, 869-870. Plate xxvii.
1905
A.J. Shearsby, On the occurrence of a bed of fossiliferous tuff and lavas between the Silurian and Middle Devonian at Cavan, Yass; similar in age and character to the Snowy River porphyries of Victoria, Proceedings of the Linnean Society of New South Wales, 26 July 1905, Part 2, 275, 288. Plate ix - Geological Sketch Map of portion of Parish of Cavan, County of Cowley, Yass, NS.W.
1906
A.J. Shearsby, Notes on the Operculate Madreporaria Rugosa [Corals] from Yass, New South Wales, Geological Magazine, V(iii), No.510, December 1906, 547, 552. Plate xxvi.
1909
Frederick Chapman, On a new species of Leperditia from the Silurian of Yass, New South Wales, Proceedings of the Royal Society of Victoria, 22, Part 1, 15 April 1909. Plates i and ii.
1910
AJ Shearsby, Native silver from Kangiara, Yass Courier, 26 April.
AJ Shearsby, Extinct Volcanoes, Yass District, Yass Courier, 24 June; Cootamundra Liberal, 25 June.
AJ Shearsby, Extinct Volcanoes, Yass District, Yass Courier, 12 July.
AJ Shearsby, Yass Lavas and Barren Jack Dam, Yass Courier, 2 August.
AJ Shearsby, Evening News, Sydney, 1910:
ANCIENT VOLCANOES. A HUGE LAVA BED. GEOLOGY OF YASS DISTRICT.
Writing on the geological formation of the Yass district, Mr. A.J. Shearsby, F.R.M.S., says— "Reports of earthquakes and volcanic eruptions reach us with more or less regularity through the daily newspapers, but fortunately for Australians they occur outside the boundaries of our island home. Such a quiescent state of affairs has not always been the happy lot of this country, but only minor quakes similar to those at Adelaide a few years ago, have been felt since a white - population invaded the land. No white man has witnessed a volcanic eruption in Australia, for all our volcanoes have been dormant for ages, and it is well nigh next to impossible to say when the last fiery eruption took place. It has been stated, however, that a member of the South Coast tribes of Aboriginals, when asked about an extinct volcano close by, said that his grandfather or greatgrandfather saw it smoke. This is the only record we have of any activity of an Australian volcano since the land was inhabited by human beings. It is not, however, of these recent and tertiary volcanoes that I wish to write, but of the old worn-out volcanoes of Yass. In a geological map of the district which I am gradually preparing enormous areas are shown composed of igneous rocks. These rocks are of two kinds, volcanic and intrusive. The latter, mainly consisting of quartz porphyries, are well known to everybody about Yass district as 'blue granites,' but, as they are very complex and their origin not yet decided, I will leave them, and return to the volcanic rocks or lavas. One of the most convenient places for examining these lavas is on the way to Taemas Bridge, where the road, just as it starts to descend to the Murrumbidgee, is cut for about three-quarters of a mile through a flinty kind of rock, stained here and there a greenish hue. This rock will be noticed to weather into very angular pieces, very different to the soft rounded masses oi the porphyry, or so-called granite, which one passes over between Waroo and the top of Bloomfield Hill.
LAYERS OF LAVA.
This peculiar flinty rock is one of the beds of ancient lava which welled out from the old volcanoes of Yass, and covered large areas of country at the beginning of the Devonian period. This bed consists of several layers or flows of lava, which are separated from each other by beds of tuff, or volcanic ash, showing that the eruptions were of a varied nature — at times a fiery stream of molten rock being poured out over the surrounding country, and at others a heavy shower of ashes, which must have turned day into darkness with its thick, impenetrable clouds. This bed of lava runs in a north-westerly direction towards the Yass River, at the Devil's Pass, and in a south-easterly direction, crossing the Murrumbidgee River, and running through Gavan Station, towards Mrs. Duff's, at West Yeumburrah, where it forms the big mountain between the homestead and the Ledeerton-road. In fact, I believe this mountain to be the remains of one of the numerous volcanoes which were responsible for this vast outpouring of molten rock. It continues away to the south-east for some miles, and then takes a complete semi-circular turn, with a diameter of about 12 miles, and runs in a north-westerly direction, parallel to the flow at Taemas and Cavan, but about two miles on the other side of the Goodradigbee River; crosses the Murrumbidgee again at Barren Jack, just above the big weir, and helps to form the big cliffs, with 'wallaby slides,' at Barren Jack Creek. Beyond this it has not been examined, but it probably extends for many miles to the north-west. It will be an interesting piece of work to discover its course, and where it joins up with the Devil's Pass flow. It is very evident that this great mass of molten rock and beds of ashes did not come from one volcano. Several vents have been mapped out, but such a vast period has elapsed since these great convulsions of nature that many of the original vents have been no doubt covered up. The remains of a large vent have been found on the Murrumbidgee River, near the junction with Narrengallen Creek. Here are beds of tuff, or volcanic ashes, with blocks of lava embedded; showing how the lava had been rended and shattered and hurled into the air, only to fall back again to the earth, and find a resting place in the ashes. And all this occurred long ages before the great Himalayas of India were forced up above the sea level. These Yass lavas vary in texture, but that they are not the same as when they were first ejected is evident when examined under the microscope. They have been subjected to such a lot of chemical and mechanical alterations during the great lapse of time since they were laid in sheets on the earth's surface that it is very hard at times to tell what they were really like originally. At Yeumburrah they consist of rhyolites—that is, close-grained flinty rocks showing a flow structure. In these rocks one can see with the naked eye the way in which the lava flowed over and under small pieces of foreign rock while in a liquid or plastic state. At another vent at the Devil's pass a similar structure is found; while in the Yass River, at the foot of the great cliff which forms part of this old volcano, quite a twisted ropy structure is noticed, which is well preserved after all these millions of years, and shows how the pasty mass swirled and bubbled before it solidified into hard everlasting rock.
THE DEVIL'S PASS.
How many residents of Yass are there, I wonder, who have visited the Devil's Pass? Very few to my knowledge have, and yet it is one of the sights of the place, well repaying the trouble of a journey there, although there is no well-formed road to the spot. Much of the track Is steep and rough, but when, one gets there the journey is forgotten, and wonder is expressed how the puny Yass River ever managed to cut its way through the immense mass of hard flinty lava of which the Devil's Pass is composed. At this spot the banks of the river are hundreds of feet high, and very precipitous. Originally this rhyolitic lava filled the ravine from beginning to end, defying, as it were, any attempt to break through. Nearly two thousand feet thickness of rock harder than granite should be a sufficient block to any body of water, one would think, but there is no withstanding the mighty forces of nature in the shape of earth-folding and earthquakes, which cause fractures even in the hardest materials. Once a line of weakness appears, in a mass of rock it will gradually be opened out under the influence of air and water. Exposure to the hot rays of the sun by day, followed by a cool or frosty night, will rend the hardest rocks to pieces, which, falling into a fast moving stream, are carried away, leaving a fresh surface to be attacked. In some such manner our little Yass River, which many years ago must have been a much more powerful stream, has been helped to cut its way through this hard, compact lava. One can well imagine the awful devastation caused by the mighty volcano close to this spot, which for many years poured forth such immense floods of molten rock, reaching a thickness of about 2000 feet in places. Assisted by the other vents, traces of which are to be seen in various parts of the district, this outpouring of lavas and ashes covered hundreds of square miles of country. Large areas have since been denuded, and helped to form the sediments at the bottom of the Devonian seas, which followed this volcanic turmoil. Most of the remainder is covered up by the shales, sandstones, and limestones (which form the present valleys of the Murrumbidgee and Goodradigbee rivers in the Yass district), these sediments being part of those laid down during the Devonian era. From the top of the old. denuded volcanic vent at the Devil's Pass, one gets a magnificent view of the surrounding district. To the north, some miles away, appears the Bowning range of hills; but looking quite strange from this point, as they are 'end on,' as it were, only one conical hill being noticed. Bowning Hill, it might be mentioned, owes its origin to the same forces which laid down the massive rocks at the Devil's Pass. It is the remains of one of the lava flows, disconnected from the other great beds, through the denudation of the intervening rock. Away to the south-east, one catches glimpses of the great ancient lava beds running through Good Hope and Cavan, where in places the lavas and tuffs are nearly a mile in thickness.
HOW THE BEDS ARE SITUATED.
The accompanying sketch map gives approximately the position of the chief beds of geological interest in Yass. The Yass porphyry is shown to the right at Boambolo. On top come the Silurian shales and limestones; then comes the great lava bed, which was laid down in the early Devonian period, when these great outpourings of molten rock had to a great extent ceased, the middle Devonian period was ushered in, and resulted in a series of beds of shales, sandstones, and limestones, containing a beautiful and varied assortment of shells, corals, sponges, etc. These beds are shown to the left. Since the deposition of the Devonian rocks there does not seem to have been much volcanic action in this area, as I have seen no traces of the Devonian beds having been intruded or overlaid by lava sheets. Earthquake action, or earth folding, has, however, been very severe, as may readily be proved by the way in which the beds have been tilted and crushed. The volcanic action, which was intermittent during the Silurian period, seems to have culminated in a prolonged and terrific outburst during the early Devonian period, as is proved by the vast beds of ashes and lavas which are shown in the section. That the volcanoes were active during the Silurian period is shown by an examination of the country within a radius of a couple of miles of the town of Yass. In Marchmont paddocks, a belt of country stretching from near the back of the rifle range to the Yass River, half a mile above the Bowspring Crossing, in one direction, and toward Douro homestead in the other direction, is composed chiefly of volcanic ashes or tuffs. Running under the big limestone cliff near Bowspring Crossing is a hard, close-grained lava. This latter also outcrops in Blackbog Creek, and is well shown as a thick sheet, dipping under the creek and the limestones, at this spot. This lava, known to the geologist as a quartz keratophyre, is easily picked out by the visitor, as it weathers out into remarkable diamond-shaped, blocks, and is one of the hardest rocks found in the district. The tuff mentioned, when weathered looks very much like shale, being soft and powdery, but when traced to bed rock,where it is solid, it is found to be almost as hard as the lava. In various parts of the paddock will be found a breccia, that is, a rock composed of small angular fragments of various rocks, cemented into a hard, solid mass. This is presumably what is known as a volcanic breccia, caused by the surrounding rocks being shattered and blown into the air with fragments of lava, and falling back to the earth, and later on consolidated with the aid of volcanic dust and water into the interesting rock as we now find it. In many other parts of the district are to be found lavae and allied rocks accompanying the Silurian sediments, showing that during the Silurian period, the volcanoes were very active. The chief deposits, however, being in the shape of thin, but numerous bands of tuff, would seem to point to the fact that the events from which the ashes came were some distance away, as fine volcanic ash or dust will very often be carried hundreds of miles by the wind ere it is deposited.
1911
AJ Shearsby, Yass Courier, 20 January 1911: Notes on the Geology of Yass. By A.J. Shearsby R.R.MS. Read before the Girls Reading Club, Yass. Read before the Gills' Reading Club, Yass.
The town of Yass is built on two distinct series of rocks - sedimentary and igneous. The sedimentary rocks consist of the inclined beds, which show good outcrops in the river banks near the two bridges, and are composed chiefly of layers of sandstone and shale, with, lower down the river, interesting deposits of limestone. These beds were laid down by the action of water during the Silurian period, and were originally quite horizontal, but such a vast amount of time has passed away since they were deposited that the shrinkage of the earth's crust, assisted by intrusions of igneous rocks, has tilted the beds, and at the present day they incline or dip under the surface so that only the edges of the beds are now exposed to view.
The intrusive rocks close to the town are the big mass of quartz porphyry of which Hibernia Crescent is composed, and the quartz porphyry which has resulted in the formation of the Manse Hill. These porphyries, known locally as granites, differ from true granites in being only partially crystalised. Their chemical composition closely approached granite; but true granite is a rock which has been consolidated at a great depth, and cooling very slowly, all the minerals such as felspar, hornblende, mica, and quartz, have completely crystalised. Porphyry, the other hand, has been forced as a pasty mass into the rocks at, or near, the surface of the earth, and cooling at a much more rapid rate, has had no time to completely crystalise; the result being a rock in which the crystals of felspar, mica, quartz, etc., are small, and instead of interlocking with each other, are embedded in a more or less granulated matrix, composed of the non-crystalised felspar, mica etc. The Hibernia Crescent bed of porphyry extends for some miles to the east before it gives way to more sedimentary beds, whilst at Yass it dips under the shales and sandstones about one hundred yards above the Hume Bridge. The Manse Hill porphyry has a similar dip, that is, south-westerly, and LIE ON TOP of the Yass beds, which are so clearly developed between Yass bridge and Cliftonwood, and DIPS UNDER the Hume beds, which form the interesting geological beds to be seen at Hatton's Corner.
The age of the Yass sedimentary beds has been fixed as Silurian, on account of the fossil remains found in them, agreeing in very many ways with the fossils which are found in the typical Silurian beds of England and Europe. At the same time it must be remembered that a very large number of the Yass fossils are new to science and peculiar to the locality. Taking the Yass beds, which consist of the many layers of shale, sandstone, and limestone, lying between the Hibernian Crescent porphyry and the Manse Hill porphyry: In the quarry nearly opposite Cliftonwood House, are found fossils of a shell known as PTERINEA LAMINOSA. It is one of the winged sea shells, very handsome in shape, and has, so far, not been discovered outside the Yass district. It is accompanied by a small fossil LEPERDITIA SHEARSBYI. This is the carapace or shell of a small crustacean, of which descendants still exist in the Yass River at present, and are popularly known as "water fleas," from their darting, erratic motion in the water, also their similarity in appearance to the flea. This fossil leperditia is also peculiar to Yass. Another fossil peculiar to the beds near Cliftonwood is the RHIZOPHYLLUM ROBUSTUM. This is a beautiful coral shaped like the front half of a shoe, that is, from the instep to the toe, and possessing a well fitting semicircular lid, which, when closed, protected the animal from the attacks of its enemies. Accompanying these are a host of interesting remains of denizens of the prehistoric seas, which covered the earth at this spot. Magnificent corals, both branching and solitary; beautiful brachiopods or lamp shells, spiral univalves, bivalves, of which one genus LINGULA exists almost unaltered in the seas of the present day; trilobites, forms of crustaceans long ago extinct, and many other relics, even down to the humble sponge, are thickly entombed in the rocks close to Yass town.
At the back of Cliftonwood House the solid blue black rock which underlies the quartz porphyry has been determined to be a "tuff"; in other words, a thick, consolidated layer of volcanic ash, which was cast out by one of the immense volcanoes which existed at that time. More volcanic ash is met with on the other side of the ridge; especially interesting are the outcrops in Marchmont paddock. We then come to the great thickness of the Hume beds which extend from the Manse Hill porphyry to some miles the other side of Bowning. These beds start with a thick bed of impure limestone, at places 80 feet thick. It is composed of alternate layers of limestone nodules, and a hard shaley material. The limestone nodules will be found to be mainly fossils, which seem to have been broken off a large coral reef which must have existed nearby, and rolled about on a beach by the action of the sea waves, before being finally deposited in the mud, which now forms the shaley binding material. (To be continued).
August - Shearsby acts as a guide to the University of Sydney Geological Field Party at Yass.
3 November - T.W. Edgeworth David and W.S. Dunn, University of Sydney, inscribe a copy of James Geike's Earth Sculpture or The Origin of Land Forms to AJ Shearsby.
1912
AJ Shearsby, The Geology of Yass District, 1911, Australian Association for the Advancement of Science, Section C, Sydney, 23 April 1912, XIII, 106, 119. Plates III - VIII. Includes Geological Sketch Map of Yass District.
AJ Shearsby, A Meteorite from Yass District, Yass Courier, 5 July.
26 July 1912, The Sydney Stock and Station Journal: The Geology of the Yass District. Some years ago a friend and I spent a little time geologising in the Yass district, and one thing that struck me at the time was the large amount of beautiful building stone there was in that part of the country. I suggested — as far as I remember now — that they should build the Capital there and ornament it with the wonderful fossil limestones so abundant in the neighbourhood. Maybe my opinions helped to get the Capital fixed there? You never know your luck, and sometimes a word in season decides a momentous question! Here is a geological pamphlet about 'The Geology of the Yass District,' by A.J. Shearsby, F.R.M.S. It is reprinted from Vol. XIII. of the journal of the 'Australasian Association for the Advancement of Science,' and was issued on April 20th, 1912. This pamphlet is scientific, so it isn't as interesting to the 'average man' as my yarn was, but if you have some geological knowledge to start with, and knew the difference between a porphyry and a trilobite, Mr. Shearsby's pamphlet Is all right. It is handsomely illustrated by a series of photographs of the essential features of the district and contains also a simple but effective sketch-map of the geological features of the place. Mr. Shearsby done good work there, and to any geological student out for a survey of the Yass district, this pamphlet will be invaluable.
AJ Shearsby, The Geology of Yass with a Bibliography for Students [manuscript], 1 October 1912.
1920
AJ Shearsby, Notes on the occurrence of Recent Travertin Formations in Oaky and Ravenswood Creeks, near Yass, New South Wales, Victorian Naturalist, XXXVII, 18 March 1920, 50.
J. Mitchell and W.S. Dun, The Atrypidae of New South Wales, with references to those recorded from other states of Australia, Proceedings of the Linnean Society of New South Wales, 45, 1920, 266-276.
1921
AJ Shearsby, Guide to Yass District, Yass, 1921.
1935
AJ Shearsby, What's in a name? [Fossils], Yass Tribune Courier, 6 June 1935.
1940
Dorothy Hill, The Silurian Rugosa of the Yass-Bowning District, N.S.W., Proceedings of the Linnean Society of New South Wales, 28August 1940, LXV, Parts 3-4, 388-420, plates xi-xiii.
Ida Brown, The stratigraphy and structure of the Silurian and Devonian rocks of Yass-Bowning district, New South Wales, Votes and Proceedings of the Royal Society of New South Wales, LXXIV, 1940, 312-340, plus map.
1947
31 July 1947, Yass Tribune Courier: Geology of Yass - Going back a trifle - 600 million years ago. Mr. A.J. Shearsby's Address. Some twenty men attended the monthly rally of the Presbyterian Men's League in St. Andrew's Vestry last Sunday evening when Mr. A.J. Shearsby gave a most interesting address on the geology of the Yass district. With the aid of a diagram and numerous specimens of rocks and fossils, Mr. Shearsby traversed the town from Hiberina Crescent to Hatton's Corner. He said that Yass is built on formations that belong to the Silurian period of the earth's history, some 600 million years oid. The granite-like rock on Hibernia Crescent (on the south side of the town) is really a volcanic ash some five to six thousand feet thick. It is the result of a tremendous volcanic eruption in the far distant past. The town itself is laid down on beds of shale, limestone and sandstone, running under Laidlaw's Hill which another bed of volcanic ash about 1800 feet thick. Then follows what is known as the Bowspring limestone bed, the remains of a great thickness of coral reefs. This limestone is followed by the Barrandella shales and on top of that the Hume limestone found at Hatton's Corner. That there are such variations in the natures of the soil in so relatively small an area is due to the fact that the volcanic eruption and subsequent erosion have left the area like a huge saucer, revealing the various layers or beds of the earth's erust at different points of its surface. Specimens of shells and trilobites (ancient ancestors of the crab) together with self-prepared microscope sections of the ancient corals, revealed clearly that the land was at one time under the sea. The league warmly thanked Mr. Shearsby for his fascinating talk, and it hoped that he will give another address at a future meeting (possibly on some section of his unique collection of stamps).
1949
30 May, Yass Tribune Courier: Geology Students Visit Yass. Accommodation Difficulties. A party of thirty four geological students from Sydney University visited Yass last week. They were accompanied Dr. Ida Brown and Dr. R.W. Browne of the University staff. The party was to comprise sixty students, but owing to accommodation difficulties, the students were divided into two parties. The second batch of students is due this week. It is expected that the new professor of geology at Sydney University, Professor Marshall, who recently arrived from England, will visit Yass this week. Last week the students visited points of interest at Dalton, (scene of the recent earth tremors), Bowning Hill, and Hatton's Corner. As in previous years, Mr A.J. Shearsby, of Yass, piloted the students in their trips round the district.
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Last updated: 9 August 2022.
Michael Organ
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