360 A. KEITH OUTLINES OF -APPALACHIAX STRUCTURE 



The existence of any pull whatever on account of a protuberance de- 

 pends on Wegener's assumption that the sima underlies the sial beneath 

 the continents. This is not supported by evidence, but rather is the con- 

 trary probable, for the deepest parts of the crust which are exposed by 

 erosion are characteristically granite — that is, sial. Furthermore, the 

 great batholiths which have come up from still greater depths are in 

 most cases granitic, or sial. Even granting that the sima does underlie 

 the sial, there is no ground in the facts of geology for Wegener's further 

 assumption that the sima would be readily pushed aside by the sial or 

 would furnish easy sliding for it. 



It must be recognized, furthermore, that any cause assigned for this 

 huge translation must have come into being since Tertiary time, because 

 the Tertiary ranges of Europe and of northern Africa are cut off at the 

 eastern Atlantic coast where North America is supposed to have parted 

 from Europe. If Spain and adjoining Africa could be forced into con- 

 tact with North America, it would be found that the Tertiary ranges of 

 Spain and Africa trend about east and west and are strongly folded, 

 while in America there is only slight tilting along lines trending north- 

 east and southwest. The same relation would obtain if the Appalachians 

 in Newfoundland were forced into contact with the same system in Great 

 Britain. The American structures trend nearly north and south, while 

 those of Great Britain trend about east and west. These complete dis- 

 cordances of structure on opposite sides of the Atlantic are supported by 

 others to such an extent that it is clear that visible structures are in 

 direct contradiction to the theory. 



The relation of the Tertiary ranges above described reduces the possi- 

 bilities in the way of cause to such as may have grown during the Qua- 

 ternary. An examination of the Quaternary beds of eastern North 

 America, however, which must under the theory have moved more than 

 2,000 miles, shows that they are almost undisturbed. It is inconceivable 

 that such a tremendous transformation could have taken place without 

 enormous dislocations and upheavals of the Quaternary and Tertiary 

 beds. From the observed Pleistocene structural geology this theory re- 

 ceives only a flat contradiction. 



Wegener cites in support of his theory certain resemblances of faunas 

 in regions that are widely separated, the argument l)eing that because 

 they are very similar they must have been deposited close together. The 

 fallacy of this argument is readily shown by the facts. Suppose that the 

 Cretaceous beds had overlapped the Appalachian system a little farther 

 and had covered the central part of it. Wegener would then have been 

 justified in assuming, for instance, that the range had been pulled apart 



