38 SURFACE GEOLOGY. 
kame, and thence flows close on its west side to White River falls. 
Along this distance of four miles we find the high plain well developed 
in New Hampshire, averaging three fourths of a mile wide. Hanover 
common, 545 feet above the sea and 172 above the river, represents its 
greatest altitude. Westward, a gradual slope descends 30 feet in one 
third mile to the kame; one third mile east the farm of the agricultural 
et nan college is 45 feet lower than the 
150-259. common; and we have the same 
height one mile south, at the high- 
. est portion of the road to West 
Horizontally 
stratified sand. 
Gravel. 
Lebanon. Observatory hill, and 
others in Norwich and Lebanon, 
Fig. 8.—SEcTion In DeLTa oF Minx are examples of outcropping ledges 
7a Ga Hanover. Scale,tinch=20 and till, surrounded by alluvium. 
eet. ki 
The lower sand shows the usual stratification of the Half a mile south-east from Han- 
outer part of a delta, dipping towards the open y 
ies A current of water has eroded a is ses 5a delta 20 to 4° feet higher 
of this, bringing a bed of gravel, upon which rests § than the common has been brought 
a later deposit of sand. i ‘ 
down by Mink brook, which, west 
from this point, has also excavated a large amount from the plain. On 
the roads to Lyme and West Lebanon such erosion as this exposes a 
clayey stratum, noticeable in the spring by remaining muddy after all the 
rest of the road has become settled and dry. Two miles north of Hano- 
ver this stratum appears from 488 to 503 feet above the sea, most nota- 
bly at the height of 495; a mile and a half south, at the north side of the 
Vale of Tempe, its height is 482; on the south side, 479 to 482; a mile 
farther south, on the north side of Mink brook, it appears from 503 to 
480, being most marked at 485; on its south side it occurs at two points, 
with heights 470 and 478 to 483, the last being most prominent; and 
about a mile farther south, at the descent just before the turn-off to the 
falls, it is very noticeable, with about the same height. It also occurs in 
Vermont at a corresponding height, just below the top of the ascent be- 
tween the depot and Norwich village. This extensive and nearly level 
stratum shows that deposition took place gradually and at the same time 
over this whole area. 
In digging the first well at Hanover (near the residence of Prof. H. E. 
Parker) a large log was found in this alluvium 40 feet below the surface, 
