268 TT. S. Hunt on some points in Dynamical Geology. 
before the American Geographical Society, New . 
12, 1872, I adduced a farther argument in favor of such a pre- 
0 
and from the time of the Calciferous sandrock to that of the 
Lower Carboniferous. [Engineering and Mining Journal, Jan. 
tinental elevations was not discussed by Hall, and is by Le- 
Conte declared to be unexplained ; while such is the case, “the 
actual mountain-formation,” to use his words, is still unaccounted 
for. That these gentle and wide-spread movements of oscilla- 
tion are, however, in some way not yet clearly explained, con- 
nected with the contracting of the nucleus and the consequent 
conforming thereto of the envelope, we can scarcely doubt, or 
that the latter, from its nature and origin, must present great 
ifferences in constitution and in flexibility in its various parts. 
