162 SURFACE GEOLOGY. 
interstratified gravel and sand. In this class, also, are, a ridge noted at 
the west line of Durham, half a mile south-west from Oyster river; the 
deposit, shown in Fig. 47, 
cut by the Nashua & Roch- S- 
ester Railroad at the divide _. 
Fig. 47.—SECTION IN SAND NEAR WHEELWRIGHT 
between Oyster and Lam- Ponp, LEE. 
prey rivers; the gravel plain Height, 30 feet. Base of section is about 150 feet 
of Lee Hill village, 190 feet above: SNe Bems 
above the sea; and the plain of nearly the same height, two miles west 
from Newmarket, on the road to Wadley’s Falls, composed of coarse 
gravel at the west, but of clear sand to a depth of 30 feet in its eastern 
portion. 
One of these deposits near Newmarket Junction, composed mainly of 
sand with no rocks embedded in it, has its surface strewn with angular 
Fig. 48.—SEcTION oN Boston & MAINE RAILROAD, } MILE 
NORTH OF NEWMARKET JUNCTION. 
Length, about 600 feet; height, 35 feet. Base of section is 
about 50 feet above the sea. 
boulders, the largest of which are 10 feet in their greatest diameter, weigh- 
ing 30 or 40 tons. The sand was deposited in the channel of a glacial 
river. When the ice on both sides and beneath it melted, this fell to the 
bottom of the shallow sea, which probably stood 150 feet above its pres- 
ent height. The boulders were then dropped on its surface by blocks or 
rafts of floating ice. 
The academy in Greenland is built on a broadly rounded, kame-like 
ridge of gravel, which at a short distance to the south-west becomes a 
nearly level plain 40 or 50 rods wide, but still farther to the south-west 
is narrowed to a typical kame. The length of this deposit is a half mile. 
Its height is nearly 100 feet above the sea. 
At a school-house half a mile south from the academy, we rise to a 
plain about 125 feet above the sea, which extends a mile to the south and 
south-east, descending with a gentle slope 25 to 40 feet in that distance. 
This plain forms the highest land between Winnicut river and Berry’s 
