22 SURFACE GEOLOGY. 
Mohawk river, but most noticeably west of the village, extending nearly 
a mile parallel with the river. Its height is about 70 feet above the river, 
and 50 above the low alluvium on each side. Its material is the same 
as that of the long kame farther south in this valley, being principally 
coarse, water-worn gravel, with abundant pebbles six inches to one foot 
in diameter. This ridge was deposited in the glacial channel of the river 
which flowed from the ice-sheet at its final melting. 
We must refer to a similar cause the slightly modified drift in Leming- 
ton, just north-west from Colebrook bridge; in Columbia, the high gravel 
terrace north of Sims stream; thence for a mile southward the moraine- 
like, level-topped or irregular drift, slightly modified, at about 100 feet 
above the river; and the coarse drift ridge on the east side of the river a 
half mile above Columbia bridge. The last is a distinct ridge, one third 
of a mile long, parallel with the river, and from 50 to 75 feet above it, 
being from 25 to 50 feet above the adjoining lowland. This may have 
been a medial moraine. It contains many angular rock-fragments from 
two to three feet in size, and seems scarcely modified, appearing like por- 
tions of the kames along Merrimack river. 
Between Columbia bridge and North Stratford the descent is rapid and 
the terraces are irregular. At Columbia bridge the highest alluvial banks 
are 48 feet above the river; at North Stratford, 119. Where the river 
now descends 1o1 feet the stratified drift of the valley shows a slope 
of only 30 feet, or about three feet to a mile. After we pass this steep 
and narrow portion, and enter a wide valley again where the river is 
comparatively level, we find the upper terrace falling much more rapidly, 
or nine feet toa mile. At Groveton it has again descended to a height 
50 feet above the river. As we approach Fifteen-miles falls, the upper 
terrace slopes very slowly down to the lower, and they can scarcely be 
distinguished as separate heights below South Lancaster. The wide 
river-plain here rises gradually from 5 or 10 to perhaps 20 or 30 feet 
above the river. 
In Stratford and Brunswick both heights of the alluvium are well 
shown, the highway being on the upper terrace and the railroad on the 
meadow. The former is about 100 feet above the river, and at Bruns- 
wick Springs, and for much of the way through Stratford, is from one 
fourth to one third of a mile wide. At Stratford Hollow depot the rail- 
