167 



GLACIAL GEOLOGY. 



It has been clearly shown that in the Permo-Carboniferous QaS8 1' 

 period, of Paleozoic time, a large portion o£ what is now Central 

 and Eastern Australia, was under the influence of ice. The 

 evidence comes trom every State of the Commonwealth as well as 

 New South Wales. 



It is well-known that in recent geological time, and indeed 

 since the appearance of Man on the Earth, Northern Europe 

 and America, including the \vhole of Great Britain north of 

 the Thames, v/ere in large part covered with moving ice, which 

 descended from the mountains, occupied valleys, and to a large 

 extent covered the plains. The evidence for this is briefly — 



a The polishing and scratching of the rock-surfaces over 



which the ice moved — Qlac'iation. 

 h The formation of beds of clay containing a miscellaneous- 

 assortment of scratched pebbles derived from the rocks 

 the ice has traversed — Boulder Gla\j. 

 c The presence of angular fragments of scratched rocks in 

 position more or less removed from their parent rock — 

 Erratics. 



d Mounds of stone left behind by the ice as it retreated 

 to higher levels when the climate became milder — 

 Jloraines. 



At Hallett's Cove, near Adelaide, and elsewhere, polished rock 

 surfaces have been found, and a specimen from this locality is 

 exhibited here. 



True boulder clay has been found in Central Australia, but 

 not in this State. 



Erratics have been found abundantly in what are known as 

 the Upper Marine Beds, wdiich underlie the Upper and Middle 

 Coal Measures, and to a slight extent in the Lower Marine Beds 

 which occur right at the base of the Permo-Carboniferous Series. 



In the "West Maitland District angular pieces of granite, 

 quartzite, slate, Devonian grit, &c., frequently showing a smoothed 



