136 FORMER LAND CONNECTIONS. 



deprived of its lateral support that collapse took place around it?' 

 borders. 



In drifting apart the segments of the crust perforce would 

 have had to squeeze up in front of them the strata composing this 

 belt of weakness ; hence the latter would have been thrown up into 

 encircling folds. These are made by the Andine Ranges on the 

 west, passing through Venezuela and continued as the Atlas-South 

 European-Iranian-Himalayan folds on the north, the Malay-Poly- 

 nesia-New Zealand crumplings on the east, and the West Antarctic 

 belt on the south, joining with Patagonia and thus completing the 

 circle. 



These folds absorbed the lateral thrust and checked further 

 spreading, but the pressures within the crust became so enormous 

 that vast quantities of igneous matter were forced out along the 

 belts of crumpling in the form of basalt or consolidated below 

 ground as granite. Inside this girdle the strata would have been 

 in tension in places, and thus an explanation is obtained for the 

 peculiar shapes of the Red Sea and Arabian Gulf, as due to the 

 opening of tears in the crust, and for the remarkable system of 

 trough-faulting extending down through Eastern Africa — the great 

 Rift Valley. 



A striking feature about the encircling folds, which all date 

 from the Tertiary, is the inflections that they make at several 

 places, thus giving us the clue to their origin. For example, the 

 Andine system doubles back sharply upon itself both near Trinidad 

 and at South Georgia, such nodal points having been less yielding 

 to the great lateral thrust and having resisted better, while the 

 region in between moved for over a thousand miles further west- 

 wards, more so in the south than in the north. In the case of 

 India the peninsular portion squeezed itself bodily for hundreds of 

 miles in a north-westerly direction between "jaws" formed by 

 Afghanistan on the one side and Burmah on the other. 



That movements of such a kind and of so great a magnitude 

 as are here postulated are not purely hypothetical is indicated 

 through the comparisons of longitude observations of certain 

 observatories in England and in the United States taken over a 

 lengthy period, that can only be interpreted as implying the actual 

 drifting apart of these countries at the present day by an amount 

 reckoned at several yards per annum. 



Life in Africa during this Time. 



Turing our attention now to the life of the Continent during 

 its dismemberment, we shall consider first that of Africa. During 

 the Jurassic and Cretaceous epochs animals were free to roam 

 northwards so far as the shores of an ocean — of which the Mediter- 

 ranean is but a remnant — that covered large parts of Arabia, 

 Palestine, Egypt, Tripoli, Algeria, and Morocco. 



Chief among the vertebrates were the Dinosaurs, some of 

 which were of truly enormous bulk, such as the gigantic Cretaceous 

 Brachiosaurus brancai of German East Africa, which must have 

 had a length of 100 feet; on the Bushmans River in Alexandria 



