EMERSON— RECURRENT TETRAHEDRAL DEFORMATIONS. 457 



Adirondacks, and dying out in faint waves against the flat unfolded 

 forelands to the southwest. The Atlantic is specially bordered by 

 Rias Coasts, indicating sinking. The Cordillera on the west were 

 caused by the tangential thrust of the sunken broad Pacific. 



Europe is a dwarf continent. It began with the fomiation of 

 the Urals in the east like the Appalachian, but stands in relation to 

 the unique Mediterranean, and is abnormally overthrust from the 

 south with a minimum addition to its area. 



Asia is a giant continent in size and shows a maximum of motion 

 and of outflowing mountain chains. 



India is a dwarf counterpart of Africa. They both have the con- 

 tinental notch on the west, and a big island off to the southeast, but 

 the volcanic area is on the west in India, while it is on the east in 

 Africa. 



Attention is called to the consideration that the tetrahedral hy- 

 pothesis does not stand or fall with the hypothesis of the suggested 

 movement of the poles. The flattening at the poles and bulging in 

 the lower latitudes is favorable to such movement, and if this tetra- 

 hedral configuration has been repeated the movement of the pole 

 may be cumulative. It is recognized that the amount 22° is beyond 

 the maximum motion of 15° suggested by G. H. Darwin as possible, 

 and yet the argument of Green does not seem to me to have been 

 completely met and the " zone of the intercontinental seas " seems to 

 plead strongly for such a movement. 



D(irwin's paper has been quoted recently as proving mathe- 

 matically that migrations of the pole sufficiently great to be of 

 geological importance have not occurred. What Darwin really said 

 is this: "We have thus clearly a state of things in which the pole 

 may wander indefinitely from its original position." By a succession 

 of considerable changes it might migrate in a devious way some 10° 

 or 15° from its geographical position at consolidation. He then 

 goes on to make the supposition by way of illustration and as if it 

 were a possible case that in the glacial period the north pole stood 

 where Greenland now stands. He goes on to say : " This would re- 

 quire extensive and numerous deformations and if the continents 

 are assumed to be permanent would it not be almost necessary to 

 give up any hypothesis which involved a very zvide excursion of the 



