GLACIAL DRIFT. 249 
Eagle the north and west sides, while Copp’s hill on the west very nearly 
completes the circle, with rifts for the entrance of the ice from Wildcat 
and Ellis rivers. On nearly every side the material low down consists 
of an immense thickness of till, cut deeply by small streams. This de- 
posit gives an evenness of slope to the hills about Jackson that is uncom- 
mon among the mountains. It is believed that the till is mainly of 
ancient glacial origin brought from the north-west, and that the latest 
ice movement smoothed it over and left many large blocks of stone and 
small moraines. The north slope of Pickett hill shows several examples 
of what appear to be local moraines. Packard speaks of a block of 
many tons’ weight upon a hill near Goodrich falls brought in this way 
only a few rods. In the neighborhood are striz pointing S. 17° W., as 
if connected with the valley movement just mentioned down the tribu- 
tary of the Wildcat river.* 
Pot-holes. In northern New England there are many examples of pot- 
holes worn in ledges far away from existing streams. These are believed 
to have been formed by currents of water derived from the melting ice- 
sheet, passing down the crevasses of the glacier. Those on the summit 
between different valleys were formerly referred to the agency of one of 
the rivers pouring over the divide into the other depression. Many of 
our examples are so situated that such a theory would not explain them. 
I append a list of the principal pot-holes that have come to my notice: 
One 4 feet deep on top of Swett’s mountain, Gilmanton. 
One of large size in Wentworth. It is on the south-west side of Carr’s mountain, 
from 300 to 500 feet above Baker’s river. 
In the ‘‘ Flume,” Dixville, I saw one, 4 feet in diameter and 7 feet deep, in the pro- 
cess of formation. 
On a ledge exposed for 200 feet, near its south end, a conical one, 2 feet in diameter 
at the top, and about 2 feet deep. It is 125 feet above the river at East Weare, and in 
the edge of Dunbarton. It is called ‘‘ Indian mortar” by the people living in the neigh- 
borhood. 
The same name is applied to a pot-hole near the top of Beech hill in New Hampton, 
about 600 feet above the valley of Lake Wukawan. It is situated on the south-western 
peak, not quite so high as the other, and perhaps 15 rods south of and 4o feet lower 
than the highest point. There are no other evidences of water action on the ledges of 
* IT have assumed that Packard’s observations were not corrected for the variation of the compass, 
as he does 
not say anything about it. 
