No. 397.] A GLACIAL POT-HOLE. 35 
and the surrounding sides have been uncovered so recently 
that we have every reason to believe the pot-hole was originally 
of very much greater depth than at present; and this, together 
with its peculiar position, renders it rather difficult to explain 
its origin and history. Its location is about half a mile back 
from the river, and the face of the cliff has a north and south 
direction. 
In the twenty-first annual report of the Regents of the Uni- 
versity of the State of New York on the condition of the State 
Cabinet of Natural History, published in Albany in 1871, is 
Fic. 3. — Pot-hole viewed from above, showing top of Utica slate layer 
where the erosion began to diminish, 
found an account of the discovery of the Cohoes Mastodon by 
Professor James Hall. He here gives an interesting description 
of the glacial pot-holes in the vicinity of the present gorge of 
the Mohawk near Cohoes. These holes are now mostly covered 
by swamps and were evidently bored out from thé general level. 
They reached a depth of from seventy to eighty feet, and their 
cross-sections varied from eight to thirty-five feet. 
From these facts it appears probable that the Catskill pot-hole 
here described originally extended to the level of the top of 
the cliff, 
Its formation was in this case similar to that which has been 
observed as now in process beneath some of the glaciers of 
Switzerland, Norway, and Sweden. In Norway they exist in 
