ORIGIN OF FOLDED MOUNTAINS PROUTY 299 



Pacific Ocean. Owing to unusual tidal and centrifugal forces, not 

 successfully explained, this great unit mass broke up into the present 

 continents, which drifted westward and Equatorward, Africa re- 

 maining relatively fixed in its present position. To account for the 

 peculiarities of drift and the position of climatic zones, the position 

 of the pole of the earth must be shifted through many degrees. 

 According to this theory, the folded mountains were formed by the 

 buckling of the sea sediments and subocean crust in front of the 

 continental ship slowly plowing through the solid-fluid subcrust. 



This theory is substantiated by the more or less perfect fit of the 

 continents when restored to their theoretical former positions. The 

 close fit of South America and Africa is obvious. The other con- 

 tinental masses do not fit so well. Greenland and North America 

 were supposedly in contact with the west coast of Europe and the 

 northwest coast of Africa. The west coast of India fitted along 

 the east coast of Africa to the north of Madagascar. Antartica and 

 Australia together overlapped the southeast coasts of South America, 

 Africa, and India. 



Professor Taylor,- of the United States, and Professor Wegener,^ 

 of Austria, are the principal advocates of the continental drift 

 theory. Professor Taylor emphasizes the equatorward (centrifugal) 

 forces, while Professor Wegener emphasizes the westward (tidal and 

 precessional) forces. 



The theory of continental drift explains the lack of coastal moun- 

 tains on the Atlantic and Arctic borders and the apparent break 

 of continuity of certain east-west mountains, as between North 

 America and Europe, northern South America and the Mediterra- 

 nean region, Argentina and South Africa. This theory might also, 

 according to R. A. Daly, " make plausible Plato's account of the lost 

 Atlantis, off the Pillars of Hercules." The mid-Atlantic ridge is 

 thought to represent a parallel strip of land left behind in the con- 

 tinental migration and, later on, modified by vulcanism along the 

 rift zone. 



Against these major appearances and minor facts, in support of 

 the theory, we find an equal or larger number of facts diametrically 

 opposed to it. There is, for instance, insufficient space in the Arctic 

 Ocean to account for the assumed southward migration of Asia and 

 the westward migration of North America. The shifting of the 

 poles could not have occurred as conjectured, because of the fact 

 that large glacial areas are known to have existed in the postulated 

 Tropics. Further, without polar shift, the theory does not account 

 for the present position of Australia and Antarctica. When detailed 

 structure and rock character of the corresponding coast lines of 

 South America and Africa are examined they do not show the ex- 



» See referencHs nt end of article. 



