68 SURFACE GEOLOGY. 
the alluvial area. These are generally separated from the lower interval 
by steep escarpments, which show that the difference in height is due to 
excavation by the river. 
The only kames found in this area were several small irregular ridges 
of coarse gravel at Woodland cemetery in Keene. The railroad cut north 
of the bridge at South Keene shows successive layers of coarse gravel 
and sand. These are 40 feet above the highest plains, being the delta 
deposits of the branch which here enters the valley. South from this 
station for one third of a mile we have irregular ridges 4o feet high at a 
short distance west of the railroad, resembling kames in form, but scarcely 
differing from common till. In the south part of Swanzey we find occa- 
sional terraces, which are sometimes of coarse gravel, from 60 to 70 feet 
above Great brook, showing that much material at first deposited here 
was afterwards channelled out by this stream and carried northward to 
the wide low plains. 
MopiFi—ep DriFT ALONG THE PEMIGEWASSET AND MERRIMACK RIVER. 
The river which drains the central portion of New Hampshire has a 
quite direct course slightly east of south. Its only departure in this 
state from the general direction is between the villages of New Hampton 
and Bristol, where it makes an offset of four miles to the west. This val- 
ley affords one of the few avenues for crossing the mountainous region. 
It begins in the deep gap of Franconia notch, between abrupt mountain 
walls, and it is at first closely enclosed by the high ranges which extend 
thence to the south. For twenty-five miles, or nearly to Plymouth, the 
valley is singularly straight, as is well seen from the summits of Lafay- 
ette and.Cannon mountains, which rise at either side of its source; or it 
forms a beautiful view from hills in Campton, with its fertile intervals and 
well tilled farms extending for several miles, beyond which, at the end of 
its long vista, are the serrated mountains cleft by the notch (vol. i, p. 551). 
Its entire length from Profile lake, Franconia, to Massachusetts line, is 
comparatively straight, forming a continuous line of depression, which is 
a principal feature in the topography of the state. The upper and lower 
portions of the river which occupies this valley are known by different 
names. For more than fifty miles from its source this river is called 
