FORMER INTERCONTINENTAL REGIONS 237 



6. South Africa and eastern South America, separated by depths in 

 excess of 10,000 feet. 



These contentions of zoogeographers have been quite generally opposed 

 by geologists, who, following the views' of Lyell, have found the demands 

 too great for their acceptance. The new science of comparative geology, 

 however, of which Professor Suess is the distinguished founder and head, 

 is now coming to the support of zoologist and botanist; so that it is now 

 pertinent for geologists to inquire concerning those regions which have 

 intimately related faunas or floras and are today separated by ocean bar- 

 riers, how the geological formations and their disposition may be com- 

 pared for the two shores, whether mountain ranges are abruptly termi- 

 nated at the coasts, and whether there are other evidences of marginal 

 faults or scarps on or near the coast. 



Katzer, from studies in Brazil,* has shown the probability that in 

 Middle Devonian time the greater part of the area of South America was 

 occupied by a moderately deep sea inclosed between continents on the 

 northeast (beginning in Guiana) and southwest, which latter may pos- 

 sibly have extended from western Chile and Patagonia westward over a 

 part of the present Pacific ocean to south Georgia. This South Pacific 

 continent has constantly increasing significance in post-Devonian time. 

 To this view Mawsonf has contributed by showing that the discontinuity 

 of the great fold chains of the South Pacific island groiips concentrically 

 arranged about the Australian continent is chiefly to be ascribed to 

 Grab en faulting, in which the land areas have risen simultaneously with 

 the sinking, to form the sea floor. Terraced coralliferous limestones are 

 found at elevations of several hundred feet (620 feet in one instance) 

 and the drop near the shore amounts to 3,000 feet. 



Since Tertiary time it can be shown that Australia has been connected 

 with many of the now isolated islands of the Indian ocean. J 



The connection of South America with Africa through Ascension, 

 Saint Paul rocks, and Tristan da Cunha, Schwarz makes very probable 

 by several lines of evidence, one of which is the discovery of rocks of 

 continental type inclosed in the lavas of the volcanic islands.§ 



On the northern border of this Africo-Brazilian continent, within the 



* Dr Friedrich Katzer : Grundziige der Geologie des unteren Amazongebietes, Leipzig, 

 1903, pp. 1-296, map. See also review by Schucbert, Journ. Geol.. vol. 14, 1906, pp. 

 722-746. 



t O. Mawson : Tbe geology of tbe New Hebrides. Proc. Linna'an Soc. New South 

 Wales, vol. 30, pt. iii, 1905, pp. 400-484, pis. 14-29. 



t Wallace : Geographical distribution of animals, vol. 2. The Australian region, pp. 

 387-485. 



§ Ernest H. L. Schwarz : The former land connection of Africa and South America. 

 Journal of Geology, vol. 14, 1906, pp. 81-90. 



