No. 200.] 
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felspathic particles, coarser than the sand of the tertiary under conside- 
ration, and besides the mineralogical characters, we have the evidence 
of superposition in many places. 
The time necessary for the removal and transportation of sands from 
the neighboring mountains to the valleys, was necessarily great, for it 
is a process which must proceed slowly, especially if affected by the 
agency of causes now in operation. 
In the 2d place, it will be seen that this formation is extensive, oc- 
cupying, if the views I have presented are correct, not only the Cham- 
plain valley, but the St. Lawrence and Hudson also. It is, there- 
fore, important on account of its extent, and will require for its per- 
fect elucidation much attention and study. 
In the 3d place; this whole formation has been deposited subsequent 
to a remarkable geological epoch, the date of which I am not able to fix. 
This epoch is marked by the wearing down and polishing of the transi- 
tion rocks of Champlain, particularly the transition limestone. The 
polished surfaces always pass beneath the tertiary, or in other words, the 
tertiary rests upon, defends and preserves those surfaces, clearly proving 
that since those currents passed over this valley, the tertiary has accu- 
mulated. 
In the 4th place; the depth of Lake Champlain is at least 600 feet 
as soundings have been made at one place to that depth without bottom. 
A large portion of the waters of the lake are therefore below the level 
of the sea. This long deep chasm is, however, constantly filling up by 
debris from the adjacent mountains. In fine, a fresh water deposit is 
rapidly making, which will be characterized by uenios helices, &c. 
In the 6th place; among the geological changes which have taken 
place in the Champlain valley, the elevation of the tertiary beds seem to 
have been the last. Whether this uplifting from the depths of the sea 
was produced gradually, or was effected by one or more movements per 
saltem, is not determined; our data are insufficient on which to form an 
opinion. Still more difficult is it to form an opinion on the questions, 
whether this valley has attained its ultimate height, and is to preserve 
its present level; the only clue we have in the decision of these ques- 
tions is, that disturbing forces have acted but feebly for many geological 
ages, and therefore it seems probable that they sleep quietly far beneath 
the surface, not again to be awakened into energetic action. 
