492 THE ICE AGE IN NORTH AMERICA. 



movement evidently reached sea-level in regions which now 

 have a warm temperate climate. 



There was a glacial epoch of great intensity at the close 

 of the carboniferous period, which has been studied with much 

 care in India, Australia, South Africa and South America. 

 In India bowlder conglomerates or "tillite" occur at points 

 which are from 700 to 800 miles apart, or if those reported 

 from Afghanistan be included, extending from latitude 35° 

 to 16°, a distance of 1,500 miles. In Australia this permo- 

 carboniferous tillite has been traced "widely in all the states 

 of the Commonwealth, including the island of Tasmania to 

 the south, with a range of latitude between 20° 30' and 43°. 

 Striated rock surfaces are often found under the old bowlder 

 clay, the directions of the scorings indicating a motion of the 

 ice in general from south to north, as might be expected; but 

 in various places the ice-sheet or sheets reached the sea, large 

 bowlders occurring in stratified shale, as if dropped from 

 ice, and marine fossils being found in close connection with 

 the beds containing bowlders." 



The most remarkable glacial deposits of this age, however, 

 or in some respects of any age, are found in South Africa, 

 where fully 1,000,000 square miles are covered with tillite 

 extending from 30° southeast for a distance of 800 miles. It 

 is found in all the provinces "from the south of Cape Colony 

 to the middle of the Transvaal or possibly the southern boun- 

 dary of Rhodesia, and from Priesk, in Cape Colony, on the 

 west to eastern Natal." The deposit is thin in the north, and 

 thick in the south where, in Cape Colony, it reaches a thick- 

 ness of 1,000 feet. No striated rock surfaces are found in the 

 south, but they abound in the north. The deposits occur at 

 elevations of from 3,000 to 6,000 feet above the sea, but along 

 the southern margin the deposits were evidently laid down in 

 water, whether salt or fresh has not been determined. The 

 most surprising thing about these deposits in South Africa is 

 that the transportation has been from the equator towards the 



