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Prof. O. P. Hubbard on Erosion in New Hampshire. 163 
parts of a river and above dams ina rapid stream, we may refer 
their production to a similar cause. 
The original features of this Orange summit were remarkable 
but they have been very much altered by the cut for the railroad, 
which has however added, by the new features developed, very 
much to its geological interest. The facts have an important 
bearing on problems which are now arising with reference to the 
geological history of New England, and are therefore worthy of 
record. A description in part, is given by Dr. C. T. Jackson in 
the Geology of New Hampshire, p. 113. 
The turnpike from Canaan on the northwest, passes some 
miles along the edge and on the sides of sand and gravel hills 
on the borders of an extensive swampy, peaty meadow, with a 
sandy bottom, which has long ramifications into the lateral valleys, 
then near a shallow pond of a few acres, which is fed by a rivulet 
coming from the hackmatae swamp at the base of the summit. 
The valley narrows rapidly, and towards the summit we find nu- 
merous long sand and gravel hills, shaped like an inverted boat, 
twenty to thirty feet high, parallel nearly to each other and to the 
general trend of the valley, with channels for surface water be- 
tween them. 
he depression or gap is several hundred feet below the gen- 
eral height of the range, and the old road formerly passed the 
summit at an elevation about forty feet above the swamp, and 
was made in the lowest channel cut by the waters formerly 
running here, and directly by the side of the “well”* made a 
slight descent across soft ground on a log causeway, then over 
a rocky ridge and down into Grafton valley. 
This well or pot-hole, as figured, appears worn down on the 
side next the road three feet lower than on the opposite ; its depth 
is eight feet; its diameter is between four and five feet at top, 
and about two feet at bottom. A large number of small, smooth 
rounded stones from this well, are in my possession, and in the 
Dartmouth cabinet is a plum shaped smooth mass of granite, 
which weighs two hundred and ninety pounds. 
The surface of the rock wherever seen, even high above the 
road track is water-worn into cavities and channels descending to 
the southward, and great numbers of pot-holes have been uncov- 
ered, which have a tendency to a linear direction nearly north 
and south. In laying out the railroad, soundings were made be- 
pe 3) - . 
laying the track about north and south, and obliterating wholly 
or in part many pot-holes of large and small size. ‘I hrough the 
kindness of my friend, R. Bakewell, Esq., I refer to his drawing 
of the section made by the railroad on its west side. j 
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* Figured, Geol. N. H, p. 114. 
