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GEOLOGY. I

I COMPARISON or RUSSIA AND AUSTRALIA. j

I As various geologists have discovered certain

physical and geological relations between the | phenomena of Russia and of this country, it may be useful to state what are the peculiar | characteristics of the former country ; and this can bo no better accomplished than by nu ana- lysis of tho Report upon the Geology of Russia, not long ago laid betöre the Geological Society of France by Mons. E. Do Vcrneuil, one of the associates of Sir It. I. Murchison and Count A. Von Keyserling, in the exploration of that vost territory. The following remarks not comprehended between brackets are, therefore, an abridgment in some degree of Do Vcrneuil'»

observations.

In a geological point of view, there is a striking contrast between the flat and nearly level regions constituting Russia Proper, and the mountains which separate it from Siberia. Over a vast area in Russia, except in the country along the Donctz, the older rocks, which arc very loosely aggregated and crum- bling, occupy a horizontal position and have undergone very little metamorphic change or elevation. On the contrary, in the Ural the most violent dislocations have tilted, folded, and reversed the palxozoic formations. The limestones ore indurated and discoloured; .lays and friable sandstones give place to argillaceous schists and grcywacke, and aro only traceable by their f'.ssil contents.

In Scandinavia, which necessarily enters into comparison with Russia, the lowest Silurian rocks repose on gneiss or the more autient schists which are denominated azoic, from the destitution of organic remains, the lowest Silurians being uucomfonuedly superimposed, and designated bj- Professor Sedeewick pro/«

soie.

The Silurian system, as developed in Sweden and Russia, is naturally divided into two periods geologically distinguished. The in- ferior ranges upwards to the culcarcous rocks of Gothland ; the superior, which is not greatly developed in Russia, save in the Ural, embraces the Gothland rocks, which are the representatives of the English Wenlock and

Ludlow beds.

Near St. Petersburgh the Devonian system, charged with its peculiar fishes, many iden-

tical with those of the old red sandstone of Scotland, and associated witii mollusca analo- gous to those of the Devonians on the Rhine, the rocks of which latter country also bear fishes identical with some in Russia, succeed to the inferior division Of the Silurian system.

The Devonian formations arc enormously developed in Russia. It separates tho carboniferous formation of Donetz from that of central Russia, and reaches towards the Teman Mountains and the Frozen Ocean, presenting in these far northern regions the same character it has on the Baltic and in the province of Valdai. In the Ural Mountains its type is different. Its epochs ure distinctly two ; the upper beds consist of red marl, en- closing fis"h, and the lower of limestones bear- ing goneatitcs, and underlaid by schists analo- gous to thoie of Nassau and the Hartz.

The carboniferous formation consists also of two natural divisions. In the north and cen- tro ot the country it is composed of beds of freestone, and black argillaceous beds contain- ing a little coal, here and there surmounted by light or occasionally magnesian, limestones. In the south, it has been much dislocated, and contains beds of good workable coal, altern a ing with grey compact limestone, charged with

marine fossils.

[Geologists cannot fail to recognise in th"* description a great resemblance to the character and conditions of the carboni-

ferous system of New South Wales. The upper series seems to find a parallel in the Sydney sandstones and Cowpasture shales and calcareous grits, and the lower bears resem- blance to the coal beds of the Hunter and Illa- warra, whiéh alternate with fossiliferous beds, fassing into limestone, as at Wollongong,

larpur'a Hill, &c]

Above the carboniferous system is laid the great series of deposits called the Permean system, which occupies in the government of Perm and the neighbouring districts an area larger than France. They abut on the flanks of the Ural, but do not penetrate the interior of that chain ; the first upheaval of which must have occurred before their deposition, and at the end of the carboniferous epoch. Conglome- rates with fossilised wood, and disseminated copper arc abundant. Limstone aud gypsum occur in beds at the base ; freestone conglome- rates at the upper part. The equivalent of these beds in other parts of Europe are the Hothrtodte liegende, Kupferschirfet, ZtchsUin, and the Gres d» V s jet; but as the type is not the same, this series in Russia is designated the Permean system.

The triamc formation is not much developed in Russia ; but the bunter Sandstein seems

| to occur in Orenburg and Vologda.

The Juraitic formation occupies several basins of considerable extent ; but the lias and Oxford oolites arc absent.

The Cre'aceous formation is found only on the southof the Devonian axis, which traverses tlie centre of Russia. It occurs in great force south of Simbirsk, but not to the north of that government ; extending into the Crimea. In this immense territory the beds of white lime- stone, with 6ilex, &c, cause it to be compared with the cretaceous beds of the North of Europe, but exhibit a dissimilarity from the type assumed in Southern Europe, Africa, and Asia, called the Mediterranean type.

[None of these formations from the Permean to the Cretaceous, both inclusive, appear to have been yet discovered in Australia, unless indeed the carboniferous beds pass upwards into Permean. Should it eventually be found that the latter do not represent any of our de- posits, it will of necessity follow that the greater part of the area now occupied by Aus- tralia must have been above water during the whole period in which the above-mentioned formations were being deposited in the noi them hemisphere ; and that considerable portions of the area were then submerged during the ter I tiary and diluvian epochs, and have since risen

(as attested by raised beaches and other phenomena,) to the present level above the sea.]

The tertiary formations occupy a most ex extensive area in Russia. The great eocene and miocene groups are divided by the granitic axis which extends from Volhynia to DoneU, the former deposits occurring to the north. The southern group is connected with Tran- sylvania and Austria.

A much greater development of tertiary beds occurs in the general area between the Aral and Caspian seas, hence called " Arah Caspian" deposits. It appears that the whole of this territory, extending to the western shores of the North Sea, was formerly occupied by KO. enormous inland basin, having no com- munication with the Mediterranean or the ocean. The Aral and Caspian seas ore tho relics oí this once vast inland, vam 0/ waten,

But whither have they receded, to leavo but the present comparatively small portions of them r And how is it, that the rocks then deposited arc now from 200 to 300 feet above the level of the existing waters. The only explanation is, that this part of Russia was ' subjected to vertical movements of elevation,

but not to inuch horizontal derangement, the ' consequence of which was the submergence of

great part of Russia during the tertiary and diluvial epochs.

The Mediterranean is now connected with the Black Sea, and this connection has given an oceanic character to the fauna of the latter, very different from that of the Aralo-Caspian territory. The shores of the Black Sea arc of the pliocene age, but there is no species of the

fossil shells of that formation identical with

living species in the Black Seo, whereas the fauna of the Caspian is very similar to that of the peculiar Aralo-Caspian beds. After tho drainage of the Aralo-Caspian basin, the de Ercssion of the Caspian was not immediately

ut gradually produced ; since shells now living in its waters ore found at variable heights in the Kalmouck Steppes. These relics defino very distinctly the anticnt shores of the an-

cient moss of waters.

[This great deposit and its peculiar features seems also to bo represented in Now South Wales, by the great plains to the westward of the Dividing Ranges. The Liverpool Plains and other similar areas appear to have been formerly occupied by inland waters which are now drained off ; the alluvial deposits from which arc found to contain shells of living species, together with the bones of gigantic animals of

1 genera yet existing.]

The tertiary ana older deposits in Russia are covered in the northern governments by traníported blocks which cover the country for 600 miles south of their origin, which, there is no doubt, was in Scandinavia and Fin- land. These drift blocks cannot have been occasioned as some authors would believe by glaciers"; bnt it is. probable, they are due to icebergs floating southwards, when Scandinavia and Russia in Europe lay still beneath the sea. The Ural must have been elevated pre- vious to this ; because its drift is all local and not transported ; and if the latter were due to olaciers, there ought to have been abundant blocks on the Ural.

This latter chain ranges through l8 degrees of latitude, deviating but little from the me- ridian. Its highest elevation is from 5000 to

«000 feet.

The axis is composed in general of talcose schist or chlorite and quartzite, whick arc re- ferred to the Silurian system. The granites of this chain arc more recent, and have burst through the eastern dislocations. Rich me- tallic veins and alluvial gold, together with gold in veins of quartz, are common. On the

west side the order of the rocks is best deve-

loped, but on the eastern igneous slopes the miner is best repaid by ores.

[Now we have here a third striking resem- blance to the condition of the Blue Mountain ranges, which in Australia run rudely in a general line, not for from the meridian, through 30 degrees of latitude in Tasmania and New Holland and New Guinea, having their high- est points at an altitude of from 5000 to 6000 feet above the sea ; with an axis of chloritic and talcose schist, and quartzitcs, with occa- sional limestones of Silurian age, in which occur metallic ores and gold in veins of quartz. Moreover granitic rocks of a comparatively

younger age break through them.

As on the flanks of the Ural, the carbonife- rous formation reposes, so in this country occurs the very same order of deposits. It is therefore highly probable, that besides the lead and copper which exist in the Blue Mountain ranges, auriferous sands will be found in the rivers flowing from them. Indeed, gold occurs not only in the veins of quartz which traverse the schist, but in the black striated cubes of pyriteB so common in the Bathurst country. Nor ought there to be any astonishment, if hereafter it bo discovered that platinum also exists in New South Wales. In respect of all other phenomena, the dividing ranges of New Holland are similar to the Ural, with the excep- tion that the slope in this hemisphere is to tho west, and the escarpment edges of the deposits to the east, and let it be observed that the general direction of the South Australian mineral ores, is nearly, if not (on the large .cale), actually parallel with the greater chain to the eastward. New South Wales will, pro- bably, on some future day, be found wonder- fully rich in metals.

So far as has yet been ascertained, the drift of the Ural Mountains seems to have its pa- rallel in that of Australia, which is all leca!, and much of it fluviatilc, deposited at the ancient mouths of the present rivers, whan the country

was at a lower level. Such is the undoubted origin of the gravel beds of the Penrith and Windsor districts. The phenomena pointed out by Captain Sturt render it far from im- probable that the interior depressed area of Australia is of similar character to the great Aralo-Caspian country.

From facts communicated to the Geological Society, Sir R. J. Murchison has already adopted the same view as the present, respect- ing the probable mineral wealth of Australia. He has even gone so far, in a letter addressed to Sir C. Lemon, and which is published in the last number of the Philosophical Magasine, as to advise that a person well acquainted with the washing of mineral sands, be sent out to Australia, speculating on the probability of auriferous alluvia being abundant, and he suggests that such will be found at the base of the western flanks of the dividing ranges.]

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Digitisation generously supported by
Vincent Fairfax Family Foundation
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