1872.] 133 [Perry. 
neath the sea, during more or less of the Newer Plistocene times. 
Beyond what has been given, little additional proof of a satisfactory © 
character has been found, either as to the superficial extent of this 
relative change of level, or as to its vertical amount. The degree of 
this change seems to have been greatest toward the east and the 
north-east. Whether there were a uniform increase in that direction 
is doubtful; exact known evidence of such increase has been, up to 
this time, evidently wanting. The utter failure to find recent marine 
. remains at a distance from the sea, in Southern New England and 
_ New York, for instance in the valleys of the Hudson and of the Con- 
necticut, while they occur in great abundance in the portions of the 
country certainly known to have been invaded by the sea, as the 
basins of the River St. Lawrence and of Lake Champlain,! is at 
least presumptive evidence against such a supposition. Now the only 
safe ground on which one can advocate a subsidence is that afforded 
by positive evidence of the presence of the sea. And of this there 
is none, beyond what has been virtually given. On what basis, then, 
has the supposition of so broad a submergence really rested? First, 
on the false presumption, that what is really true of one thing is nec- 
essarily true of another, which has some resemblance. Marine re- 
mains having been actually found in certain stratified beds of clay 
and sand, all other beds of about the same age which seem, and in 
points are, somewhat similar, have been regarded, without proof and 
in spite of evidence to the contrary, as of marine origin. Another 
consideration has perhaps exerted an unconscious influence in the 
production of this result. I refer to the necessity of getting rid of 
unauthorized hypotheses, after they have served the temporary pur- 
pose for which they are devised, lest they prove an incumbrance. 
Thus, in the present case ; after the assumption of a continental ele- 
vation, with the view of accounting for one class of facts,—after the 
land has been lifted up in imagination, as it has been by so many 
geologists,—it was necessary to suppose a continental depression; the 
continent must be got down again, in order to the explanation of 
another set of facts, and in order that it may be brought into the 
position in which we now find it. 
1 As an evidence of the extraordinary prevalence of Plistocene marine remains 
in the valley of Lake Champlain, I may add that‘I have found them in every Ver- 
mont township bordering this body of water, between Orwell and the Canada 
line; also at an almost equal number of localities on the western shore, between 
Ticonderoga and Rouse’s Point; likewise, and sometimes in great profusion, on very 
many of the islands that stud the surface of this charming lake. 
