1872 ] tai [Perry, 
ten with apparently too little regard to facts. He has evidently 
failed to work out many Post-Tertiary problems on which he dis- 
courses, by a steady search after the truth; by an unwearied ques- 
tioning of the facts, as they may be seen in the great field-book of 
the naturalist. 
But this suggests, and leads me once more to remark, that Prof. 
Dana’s views of the Post-Tertiary era in New England seem to be 
largely theoretical and formal. I do not object to hypotheses; I 
would not exclude theories, when there is any ground for them; I 
would only require that speculation be confined to facts, and in no 
wise allowed to outrun them. But when it is mere theory, either 
. virtually apart from facts, or altogether without them, the case is 
different. As an instance, take the doctrine of Elevation, as applied 
by Professor Dana to the Ice period. So far as I can make out, it 
does not rest either actually or legitimately on a single fact. Thus I 
fail to find in his statements real and substantial expositions of the es- 
sential truth of nature, genuine settings forth, and so true representa- 
tions of the actual processes which the manifold facts at once witness 
and symbolize. Seen in this light, his view of glaciers and of the 
Ice-period generally, is very inadequate and altogether unsatisfactory. 
Finding the iceberg hypothesis untenable, failing to get help from the 
theory of wave translatioa, seeing that much could be theoretically 
explained on the supposition of an immense ice-sheet, he appears to 
have boldly adopted, without having mastered, the latter view. In- 
deed, his adoption of it, as almost every page of his paper shows, is 
on negative grounds, and not from a thorough and exhaustive under- 
standing of the practical working of the principles involved. From 
such an apprehension of truth, even of vital truth, the best that can 
be reasonably expected is a fine theory, but one that is withal formal 
and lifeless. Had he really mastered the view, his reception of it 
would have been more than its half-adoption, and would have 
taucht him the utter uselessness of his elevation hypothesis. 
J have thus frankly thrown out hints in regard to portions of the 
Geologic history of New England, thus freely spoken of Prof. Dana’s 
contribution. Some of the positions advanced by him I have been 
disposed to commend ; upon others to pass strictures, according as 
Thave found them well-founded or not entitled to confidence. Less 
has been said of excellences, for they bear witness of themselves; 
more of supposed defects, since amidst much good, inadequate or false 
views are liable to be overlooked, and accordingly accepted as with- 
out spot and true. And all this has been done in the way of discus- 
