+ 
162 Prof. O. P. Hubbard on Erosion in New Hampshire. 
The direction of the dike is about N.N.E. in a line with the 
bridge across the river, and it is quite probable the dike extends 
along distance either way and was once a barrier to the river. 
The Connecticut river is here bounded on the east by a high 
rocky mountain, and the position and appearances of the dike in 
relation to the river, suggest the inference that the removal of the 
trap is a fair measure of the erosion at this place, and, at least in 
part, of that produced by the action of the river (sixty feet). 
A small stream from the west ina deep rocky channel just 
north of the bluff removed, seems to have had its course deflect- 
so as to empty into the Connecticut river just north of the in- 
tersection of the latter river and the dike, and their joint force 
has continued to reduce the level of the latter so as to afford the 
ree passage of the river. 
(f.) We'may mention here, before proceeding, a few facts 
brought to light by the different railroad surveys in New Hamp- 
shire and Vermont. The Rutland and Burlington Railroad crosses 
the Green Mountains at Mount Holly gap, at a level of 1350 feet 
above the Connecticut river.* In this place a cut was made 
through a muck swamp, which exhumed some remarkable ele- 
phantine remains. The White Mountain Railroad survey from 
the Connecticut up the Ammonoosuck, passes the summit in or 
near Whitefield, at six hundred and fifty feet above the Connecti- 
cut, and this within twelve miles of Fabyan’s in the White Moun- 
tains. ‘The Passumpsic Railroad overcomes the summit in Sutton 
at about nine hundred feet above the Connecticut at West Leba- 
non. The Central Railroad of Vermont passes the summit be- 
streams to be the effect of water, we shall be justified in refer- 
ring them to a similar agency, i. e. rin motion. Should we 
observe phenomena like what are frequently seen, in the less rapid 
* See profiles and reports of these roads. 
Zn Am. Assoc. for Ady. Science, held at Cambrid 
tinier 4: Ane8: soc. for Ady. Science, held at Cambridge, Sep- 
