352 A. p. COLEMAN GLACIAL PERIODS AND GEOLOGICAL THEORIES 



It is worthy of note that the whole area of glaciation in Africa is prob- 

 ably not yet known, since the striations and directions of transport of 

 blocks are all southward. It is quite likely that the center of glaciation 

 was north of latitude 25° or even within the tropics, and that the ice 

 flowed out in all directions, north as well as south. The reported finding 

 of a glacial boulder conglomerate by Kort in Togoland suggests that de- 

 cisive proofs of northward ice movements may yet be found. 



The Indian sheet also appears to have moved only in one direction, 

 northward, or away from the equator, so far as one can infer from the 

 transport of boulders, since striated surfaces seem rare.^^ Oldham notes 

 that boulders in the Salt Eange conglomerate are like rocks 750 miles to 

 the south ;^° and this is confirmed by Koken.^^ 



To the three great areas of glaciation within regions now warm tem- 

 perate or tropical must be added southern Brazil, where Dr Orville Derby 

 and Dr I. C. White have found what they believe to be a glacial conglom- 

 erate beneath coal measures."^* It is noteworthy, as shown by the paleo- 

 botanist, Dr David White, and other paleontologists, that all these glacial 

 beds are followed by coal seams and are accompanied by cold climate 

 plants of the glossopteris or gangamopteris flora, showing that the diflEerent 

 regions mentioned were glaciated in the same geological period.^* 



With such tremendous developments of ice action in the southern 

 hemisphere and in India, in regions now so warm, one naturally asks. 

 What occurred at this time in the rest of the world? But the records 

 elsewhere are very meager. In Eussia a Permian boulder conglomerate, 

 with the glossopteris flora, has been found in the eastern Urals by A. 

 Karpinsky, who believes it to be glacial, while Doctor Tschernyschew 

 would only say that it is probably glacial.^" 



The finding of a supposed glacial deposit of similar age by Eamsay in 

 England in 1855^^ seems to have been disputed by almost all other British 

 geologists, though Oldham, fresh from the Indian region, believes that 

 these boulder beds are probably glacial after all — not true boixlder clay, 



^ The only mention of the direction of strise which I have found is by Medlicot and 

 Blandford, Manual of Geology of India, p. 229, where the motion was northeast by north. 



1° Geology of India, p. 120. 



" Neues Jahrbuch fiir Mineralogie, Festband, 1907. 



IS Science, vol. xsiv, no. 012, 1906, p. 377. 



i" .Journal of Geology, vol. xiv, no. 2, 1907, pp. 615-633. 



-" Geological Survey of India, Records, vol. sxxi, part 3, 1904, pp. 112-113. (Trans- 

 lated by Professor P. Briihl from Bulletin of Commercial Geology, tome vlii, pp. 204- 

 206.) 



21 Quarterly Journal of the Geological Society, 1855, p. 185. 



