474 THE PERMIAN PERIOD 



Permian glacial formations. The most remarkable fact about 

 the Permian as a whole is that it includes formations of glacial origin, 

 and that these occur down to and even within the tropics. Such 

 formations are found in all the continents which have large areas in 

 low latitudes. 



In Australia, strata of Permian glacial drift are interbedded with 

 marine formations and coal beds, the aggregate thickness of the 

 whole being not less than 2,000 feet. The recurrence of the bowlder 

 beds points to the repeated recurrence of glacial conditions, and the 

 great thickness both of clastic beds and of the many included coal 

 beds points to the great duration of the period through which the 

 several glacial epochs were distributed. 



Counting Tasmania, the glaciation of Australia had a known 

 range of nearly 22 in latitude, and about 35 in longitude, though 

 it is perhaps not probable that all the area within these limits was 

 glaciated. The glacial formations are known chiefly at low levels, 

 descending in some places nearly to the sea. Not only is the alti- 

 tude of the region low now, but it was probably low during glacia- 

 tion, as shown by the interbedding of glacial and marine formations. 



The fossils of the marine beds associated with the glacial 

 deposits are similar to those of the Carboniferous (Pennsylvanian) 

 period elsewhere, but the plants of the associated coal have a 

 Triassic facies. Permian fish remains are found above all the bowl- 

 der beds, suggesting that the glacial conditions were over before the 

 end of the Permian. The plant fossils therefore indicate that the 

 period of glaciation was late Permian or early Triassic; the marine 

 fossils, that it was late Carboniferous or early Permian. 



In India, too, there are glacial formations ( Talchir conglomerate) 

 of about the same age, with fossil plants like those of Australia in 

 associated beds. The bed on which the glacial formations rest is 

 in some places striated and roche-moutonneed, as beneath modern 

 glacial deposits. These formations are even more remarkable than 

 those of Australia, for they reach several degrees within the Tropic 

 of Cancer (to Lat. 18). Similar formations appear farther north in 

 India where marine Permian beds overlie the glacial series. 



In South Africa many of the bowlders of the glacial beds (Dwyka 

 conglomerate) are striated, and the bed on which the glacial con- 

 glomerate rests shows indisputable marks of ice action in many 

 places. The glacial beds are believed to have extended to 26 40'. 

 In South America glacial conglomerates also are present in the 



