MODIFIED DRIFT ALONG CONNECTICUT RIVER. 37 
vated by the river. The question which we see no satisfactory way to 
answer is, How came the hollow which contains the pond to be formed 
or left vacant, when the material of the otherwise nearly level plain was 
deposited? Probably it marks the site of a mass of ice, broken from the 
glacier, brought down by the flood, and finally stranded at this spot. The 
principal objection to this hypothesis is the rapidity of deposition required. 
A large amount of modified drift has been brought down by Grant’s 
brook, forming the plain on which Lyme village is built. The common 
has a slope of fifteen feet, and in a short distance farther east the same 
deposit rises eighty feet more, to 635 feet above the sea, or go feet 
higher than the water-shed between the village and Post pond. 
Anctent River-bed. In Norwich occurs the most interesting example 
seen by us of a well-marked ancient river-bed high above its present 
level. This extends two miles from Pompanoosuc river, one third mile 
above its mouth, to the bend of Connecticut river a half mile south of 
Tilden pond, which lies in a depression of this old channel. Its highest 
point, from which there is a gradual descent both ways, is 520 feet above 
the sea, or 145 feet above the river. West and south-west from this point 
is a plain, from 30 to 40 feet higher; at the north-west the alluvium forms 
a delta-like slope with no level top. South-west from Tilden pond the 
original high plain has been excavated by springs and small streams to a 
very irregular surface of hillocks and ridges. On the east side of this 
ancient channel is the steep gravel kame, which for a while turned the 
Pompanoosuc river in this course, till a direct passage was cut through 
its ridge. 
Norwich village, 525 feet above the sea, is situated on a terrace-plain 
of Bloody brook, which extends three fourths of a mile above the village, 
Hanover Ag. Coll. Delta of 
common. farm, Mink Br. 
w Terrace of Bloody Br., os 
a 545- 500. 564. 
wn, ise] 
8 ~=- Norwich village, 52s. g g 
Fig. 7.—SECTION IN NORWICH AND HAROvER. “Length, 3 miles. sea, 
rising 30 feet. At one mile south the modified drift on the Vermont side 
is interrupted by a ledgy hill. 
Two miles north of Hanover the Connecticut river has cut through the 
