210 J. D. Dana on the origin of the Earth’s Features. 
gravity; for this produces none: and ho 
. Mr. Hall’s hypothesis has its cause for subsidence, but none 
for the lifting of the thickened sunken crust into mountains. 
greatest thickness. At first thought, it would seem almost 1n- 
credible that the upliftings of mountains, whatever their mode 
the disturbing or uplifting force is lateral action or pressure from 
noted that the thick accumulations are produced just where 0S- 
cillations and disturbances, or great yieldings in the crust, had 
been in progress through the long preceding ages (attending 
