88 Charles Schuchert — Historical Geology, 1818-1918. 



land of tillites, and here in 1870 Sutherland pointed out 

 that the conglomerates of the Karroo formation were of 

 glacial origin. Australia also has Permian glacial 

 deposits, and they are known widely in eastern Brazil, 

 the Falkland Islands, the vicinity of Boston, and else- 

 where. So convincing is this testimony that all geolo- 

 gists are now ready to accept the conclusion that a 

 glacial climate was as wide-spread in early Permian time 

 as was that of the Pleistocene. 1 



In South Africa, beneath the marine Lower Devonian, 

 occurs the Table Mountain series, 5000 feet thick. The 

 series is essentially one of quartzites, with zones of shales 

 or slates and with striated pebbles up to 15 inches long. 

 The latter occur in pockets and seem to be of glacial origin. 

 There are here no typical tillites, and no striated under- 

 grounds have so far been found. While the evidence of 

 the deposits appears to favor the conclusion that the 

 Table Mountain strata were laid down in cold waters with 

 floating ice derived from glaciers, it is as yet impossible 

 to assign these sediments a definite geologic age. They 

 are certainly not younger than the Lower Devonian, but 

 it has not yet been established to what period of the 

 early Paleozoic they belong. 



In southeastern Australia occur tillites of wide distri- 

 bution that lie conformably beneath, but sharply sep- 

 arated from the fossiliferous marine Lower Cambrian 

 strata. David (1907), Howchin (1908), and other Aus- 

 tralian geologists think they are of Cambrian time, but 

 to the writer they seem more probably late Proterozoic 

 in age. In arctic Norway Reusch discovered unmistak- 

 able tillites in 1891, and this occurrence was confirmed by 

 Strahan in 1897. It is not yet certainly known what 

 their age is, but it appears to be late Proterozoic rather 

 than early Paleozoic. Other undated Proterozoic tillites 

 occur in China (Willis and Blackwelder 1907), Africa 

 (Schwarz 1906), India (Vredenburg 1907), Canada 

 (Coleman 1908), and possibly in Scotland. 



The oldest known tillites are described by Coleman in 



1 For more detail in regard to these tillites and the older ones see Climates 

 of Geologic Time, by Charles Schuchert, being Chapter XXI in Hunting- 

 ton 's Climatic Factor as Illustrated in Arid America, Publication No. 

 192 of the Carnegie Institution of Washington, 1914. Also Arthur P. 

 Coleman's presidential address before the Geological Society of America 

 in 1915. Dry Land in Geology, published in the Society's Bulletin, 27, 

 175, 1916. 



