Geological History during Tertiary Epoch . 103 
flourished in the seas, and left their remains to be entombed in the 
sediments ; huge sharks and toothed whales lived in the waters ; 
coral reefs fringed the coasts, and furnished tho materials for the 
limestones. On the land we can also trace a different set of con- 
ditions to those now observable ; the crest of the eastern portion 
of the Main Divide was further north, and the mountains were 
still very much loftier than now, but more in the form of elevated 
plateaux, intersected by broad valleys and high ridges, and less 
sculptured and abrupt in their configuration than at present. 
These conclusions are based on tho appearance of the vestiges 
which remain of the river deposits of the period, such as the 
gravels* beneath tho basalt of the . Dargo High Plains, and other 
places along the Main Divide, which unmistakably indicate that 
the streams which deposited them had their sources much further 
north, and, consequently, that the Main Divide of that period was 
further inland than the present one. 
It is- noticeable that the High Plains forming portion of the 
Main Divide, lying between the Dargo and Cobnngra Rivers and 
Connor's Plain, between the Macalister and Goulburn Rivers, are 
now among the highest portions of the Main Divide, yet they 
represent portions of what were mountain valleys during the 
Middle Tertiary epoch. (Fig. 47.) 
The vegetation was then of different character to that now 
flourishing in Victoria. Instead of the now prevailing species of 
eucalypts, lauraceous trees of various species appear to have pre- 
dominated, the fossil leaves of the Dargo High Plains and Bacchus 
Marsh being, as described by Professor McCoy, of that class. 
Professor McCoy also remarks, with reference to one of the fossil 
leaves, Salisburia Murrayi (McCoy), from tho Dargo High 
Plains, that it is nearly allied to some Miocene forms from the 
Arctic regions. Lakes occupied broad hollows along the river 
courses, and in them deposits of lignite, clay, sand, and mud were 
accumulated. It is impossible to say what part, if any, was 
played by terrestrial glacial action during this period, but the width 
of tho old river deposits, and tho character of the materials, indi- 
cate large volumes of water as having acted in their transport and 
arrangement. This, taken in connexion with the fact that the 
mountains from which the rivers rose were very much higher than 
those of the present day, justifies the belief that the loftier summits 
were capped with snow, and that glaciers existed in the higher 
ravines. The absence of ice-grooves in the rocks has been 
adduced ns an argument against this conjecture; but when it is 
considered that the rocks have since been denuded for many 
hundreds, perhaps thousands, of feet below what was their surface 
in those times, and that consequently any ice marks must have been 
wholly obliterated, the objection ceases to carry much weight.* 
* Decent observers, Dr. von Lcndenfcld and Mr. James Stirling, have 
observed what they regard as distinct traces of glacial action among the 
higher portions of the Australian Alps. 
