452 J. LeConte— Formation of the Karth-surface. 
trough, and the whole bulging took place afterward by the 
crushing together of its strata. But now (if I understand 
him aright, for he is still not very clear) Mr. Hunt says that 
the Appalachian plateau or chain was formed by the same 
unknown process by which the continent was elevated ; that it 
was formed by continental elevation, which from some unknown 
cause was greater in the Appalachian region. I wish much he 
had clearly expressed this at first; it would have saved much 
useless discussion. I confess, however, I can not find anything 
like this in his previous papers or in the writings of Prof. Hall. 
In the early presentation of a difficult subject, however, some 
want of clearness is pardonable i 
7. According to my view, foldings are a necessary concoml- 
tant of mountain formation; but Mr. Hunt, p. 267, thinks both 
cleavage and foldings are mere accidents, unnecessary to moun- 
tain structure ; and he cites examples of mountains on the upper 
Mississippi composed of perfectly horizontal strata, and of Cats- 
ill mountain composed of nearly horizontal strata, uncompli- 
cated with foldings. I could add other examples from my own 
observations on the Sierra chain. Mt. Dana, a magnificent peak 
more than 13,300 feet high, on the very crest of the Sierras, 1s 
composed of strata which seem to be perfectly horizontal. 
this is no objection to my theory ; itis only an example of the 
confusion of thought of which I speak above. The explana- 
tion of the difference between mountain formation and mountain 
ins, not of isolated peaks. Mountain chains are, I believe, al- 
this point doubtful; on the contrary, I say “ evidences are daily 
accumulating ” on this point ; not by my labors; for I was on the 
_ Pacific coast; but by the labors of others. I of course refe 
to the very evidence which Mr. Hunt mentions, but did not 
think it necessary to mention names in connection with facts 80 
