Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/457

 gical period. The enormous range of deep-sea corals is now admitted ; and it is certainly very remarkable that so few of them should have become common to the European and Australian tertiary deposits. The absence of any littoral connexion between Australia and the tracts to the north of it during the whole of the tertiary period, and the remoteness of the south of its area from any great centres of frequent terrestrial oscillations, may explain the persistence of type which is so characteristic of a large portion of its fauna and flora*. This persistence was infinitely less in Europe, on account of the more frequent changes in the physical geology of its area, such changes inducing emigration of some forms, unusual competition with others, and occasional free scope for rapid multiplication. Hence the distant and comparatively quiet area of Australia was tenanted by the same species, whilst vast biological and geological alterations took place in the area which was formerly considered the type by which all others could be compared.

The permanent upheaval of the central and northern area of Australia, the extinction of its volcanoes, and the change in its coral fauna were grand phenomena. Considering that a relatively identical age is given to the great upheavals of the Alps and Himalayas, there is some reason for asserting that the Australian and New-Zealandic upheaval was more or less synchronous with them, with the closure of the Isthmus of Panama, and with the depression of the areas on either side of the American continent.

The denudation which occurred during the upheaval of the Australian area was enormous, and it is to be estimated by the extent of the unfossiliferous deposits which cover the fossiliferous marine Tertiaries. There are no proofs of any glacial phenomena in Australia ; and subaerial denudation probably went on during the whole of that vast period, and has continued. The whole of the paying gold- drifts were formed after the deposition of the marine fossiliferous strata ; and thus the sandy ferruginous clays, coarse pebble-grits, and hard ironstone cements and conglomerates, together with the lava- plains to the north of Cape Otway, are younger than the Mount- Gambier polyzoan limestones. Above these latter deposits are great beds of blown sand, dunes, lacustrine formations, raised beaches, and estuarine deposits. There are some lignites, shelly and siliceous sands, and volcanic ashes between these two series, which attain the height of 130 feet at the mouth of the river Gellibrand.

These remarks will have prepared us for a condemnation of the terminology usually employed by Australian geologists. I would suggest that the word Tertiary should be only used relatively in Australian geology, and that the strata (so ably mapped by the surveyors) which are above the carbonaceous sandstones should be called Cainozoic. The term Lower Cainozoic would refer to all the deposits beneath the Mount-Grambier series, the Middle to that deposit, and the Upper to all above.

It would be as well not to establish a too local terminology ; for

connected with Australia at tin's time.
 * The islands of Papua and to the south of the Straits of Bali were probably

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