EARLY CAMBRIAN GLACIAL PERIOD 353 



but morainic materials with scratched stones which have been reasserted 

 by water, apparently kame deposits.^^ 



In North America a supposed Permian moraine in Prince Edward 

 island has been described and sketched by Mr P. Bain, but no striated 

 stones are mentioned in his account.^* 



Dr "Whitman Cross describes and shows a photograph of a boulder con- 

 glomerate that strongly suggests glaciation in the Permian ( ?) Eed beds 

 of Colorado, but makes no reference to ice action in his account of the 

 region.^* It might be worth examining for scratched stones. 



As in the Pleistocene, there seems to have been an impressive grouping 

 of the great ice-sheets in a special quarter, this time in the neighborhood 

 of the present Indian ocean; and their nearness to the equator, on low 

 ground and reaching the sea, makes it all the more puzzling that so little 

 evidence of glacial work should be found in higher latitudes. 



The early Cambrian Glacial Period 



Gradually proofs of an early Cambrian or late pre-Cambrian ice age 

 have been accumulating, and its effects seem sufficiently widespread to be 

 included in the present discussion, since they are found in various places 

 both north and south of the eqiiator. Some of the localities are within 

 the Arctic circle, such as northern ISTorway^^ and Spitzbergen,^^ where 

 glacial conditions might be expected if the earth then had its climate 

 arranged in zones ; but others are in parts of the world now having tem- 

 perate or warm climates. Among the latter is the glacial conglomerate 

 reported by Mr Bailey Willis from the Yangtzi canyon, latitude 31°, in 

 China, from which beautifully glaciated stones were obtained.^^ 



Tillites of this age are, however, much better displayed in the southern 

 hemisphere, in Australia and South Africa. The Aiistralian Association 

 for the Advancement of Science has for a number of years published 

 reports of a committee appointed to examine deposits belonging to ancient 

 ice ages in the different states, and in these reports there are not only 

 accounts of the Permo-Carboniferous tillites, but also descriptions of sim- 

 ilar rocks from the basal Cambrian. Mr Howchin has been specially suc- 



23 Ibid., 1894, pp. 463 to 468. 



25 Canadian Record of Science, vol. ii, 1887, pp. 341-343. 



" Journal of Geology, vol. xv, 1907, pp. 662-665. 



25 Norges geologiska Undersogelse ; Det nordlige Norges Geologi, pp. 26-34. 1891 ; and 

 Strahan in Journal of the Geological Society of London, vol. liii, 1897, pp. 137-146. 



=« Gregory : Climatic variations. Mexican Congress, p. 7. 



^ Carnegie Institution of Washington. 1907. Research in China, vol. i, part L p. 267 : 

 also Chamberlin and Salisbury's Geology, vol. ii, pp. 273-274. 



