BY PROFESSOR W. J. STEPHENS, M.A., F.G.S. 1117 



(Cockatoo Island) and elsewhere on the Eastern Coast of Aus- 

 tralia, and known everywhere by the late W. B. Clarke's name of 

 " The Hawkesbury Formation." 



Now in this formation, as was stated in the previous note upon 

 the Biloela fossil, there are abundant evidences of the action of 

 drift ice. At the present moment I am not aware of any direct 

 evidence of glacier action. Still the existence of glaciers in the 

 mountainous regions from which the drift is derived must be 

 postulated if we find in the fluviatile deposits unmistakable tokens 

 of glacial action. Since these have been ascertained, we need not 

 argue the question of the possibility of glaciers. But we must at 

 the same time admit that there is no evidence for a Glacial period 

 upon the present line of coast of New South Wales. Moreover, 

 it may be boldly asserted that all that we know of the formation 

 of glaciers will lead us to locate them upon the western rather 

 than on the eastern shores of lands, whose climatic or meteorological 

 conditions might otherwise render their formation possible. 



However, the evidence as to Drift ice, carried down by great 

 rivers in ancient times as now in the present day by the Rhine, the 

 St. Lawrence, and scores of other streams, seems conclusive. In 

 short we may positively say that the Hawkesbury sandstones 

 were deposited during a period in which there were upland 

 glaciers, and tremendous spring and summer floods. There are 

 many regions similarly affected now, and there have been many 

 more, as any student of geology knows. 



But at the same time we have to recognize the existence of a 

 warm temperate climate, in which the luxuriant Fern vegetation, 

 Ganoid Fish, Unionida?, and last, though the most important, 

 large Labyrinth dont Amphibians could exist. 



The same phenomena are presented by Triassic strata all over 

 the world, and lead us to the conclusion that the period during 

 which this formation, with all its singular and transitional fauna 

 and flora, was developed, was one during which the earth's orbit 

 was in one of its stages of extreme eccentricity, and the globe 

 itself subjected to extraordinary changes of climate, reciprocating 



