66 SURFACE GEOLOGY. 
present water-shed. Along the half mile between this summit and the 
lake, kame-like banks of gravel and sand are found; but in general the 
shores of the lake are destitute of modified drift, being composed of till 
or ledge. The heights of these points, in feet above the sea, are as fol- 
lows: Sunapee lake, low to high water, 1,090 to 1,103; Newbury summit, 
1,130; top of railroad cut, 1,181; pot-hole, about 1,175; lowest point over 
which water could flow towards the Merrimack river, 400 feet south-west 
from the rock-cut, 1,161. It seems probable that when this pot-hole was 
formed, the lower avenue at the south-west was still filled with ice. 
Another pot-hole, 10 inches in diameter and 3 feet deep, the origin of 
which we cannot explain, occurs about 20 rods north of Newbury station, 
at the shore of Sunapee lake, halfway between high and low water. There 
is no rivulet or depression leading to the lake at this point. 
In Warwick, Mass., two miles north-east from the village, the drainage 
during part of the Champlain period was also over the present line of 
water-shed, which separates Ashuelot and Miller’s rivers.* The current 
here was from north to south, as shown by an area 40 feet square of in- 
disputably water-worn ledges, with numerous pot-holes, which are locally 
known as “Indian kettles.” This place is near the lowest point of the 
water-shed, which is a swamp perhaps 25 feet below these water-worn 
rocks. While the ‘pot-holes were being formed here, the lowest place 
over which water could have flowed was probably occupied by an un- 
melted portion of the ice-sheet, as at Newbury summit. 
LitTLe SuNAPEE Lake, NEw Lonpon. 
The peculiar form of this lake, as shown on the county map, led to an 
examination of its surface geology. It is a mile and a half long from 
east to west, and is divided into nearly equal parts by a kame-like tongue 
of land, which extends fully a half mile from north to south, leaving at 
the south shore only a shallow channel about 50 feet wide. It is princi- 
pally surrounded by gently sloping hills of ledge or till, but a narrow 
margin of alluvium, 10 feet in height, borders its north-east shore. The 
materials of the dividing peninsula are sand or gravel, with boulders at its 
south end. Its width is less than 100 feet and its height about six feet, 
where it is joined to the north shore. The central portion is about a 
* Jackson’s Final Report on Geology of New Hampshire, p. 282. 
