J. LeConte—Structure and Origin of Mountains. 109 
brought out by Professor Dana and Archdeacon Pratt; and 
the latter had at one time extended the idea so as to include 
also mountain chains, although he afterward admitted lateral 
pressure as the more probable cause of these latter. ow, 
according to the view that continents and ocean bottoms are 
* Penn Monthly, May, 1876, p. 372. 
+ Archdeacon Pratt, it is true, in the earlier editions of his “Figure of the 
Earth,” attributed the formation of mountain chains, especially the Himalayas, to 
