Connecticut River Vi alley. 209 
Descent of the tributartes.—The abrupt and mountainous charac- 
ter of so large a part of the valley, causes floods to be sudden and cur- 
rents rapid, in the tributary streams. In many tributaries, the descent 
averages, thirty, forty, sixty, and in some more than one hundred 
feet ina mile. On the White Mountains is seen a small, clear, icy 
looking lake, five thousand feet above the level of the sea. It isthe 
highest source of the lower Ammonoosuck: the stream which issues 
from this lake falls four thousand feet in about two miles. It is but 
just perceptible, except during or after violent rains, when it is seen 
bounding from rock to rock in its downward course, sparkling and 
white, as ifa snow drift had been dashed against the dark side of 
the mountain, from its summit to its base. 
Lakes.—About two hundred small lakes, from less than one mile 
to two and three miles long, lie scattered over the mountainous sur- 
face of the Connecticut river valley, placed, almost without exception, 
at or very near the sources of tributary streams. ‘The Mascomy 
lake in Lebanon, N. H., is seven miles long, and the Sunapee, the 
largest in the valley, is about twelve miles. ‘The latter hes so near 
the centre of the dividing ridge, that a channel, excavated to no ex- 
cessive depth, would change the course of its stream and turn it 
away from Connecticut river into the Merrimack. As the extent of 
country drained near the sources of streams is small, the quantity of 
earth collected in such positions is also small, and has not yet filled 
the rocky basins, where lakes remain. But following the courses of 
the tributaries farther down, small meadows appear, many of which, 
doubtless, occupy the places of former lakes, whose basins have been 
filled by depositions of earth, collected and washed down in the now 
longer courses and multiplied branches of the stream. Augmented 
currents may, also, have worn deeper the channels at the outlets, and 
drained the lower lakes, leaving their beds uncovered which soon 
become clothed with vegetation. 
JlJ. Eartruy Formations. 
Depth of earth.—Along the Connecticut, and often near its tribu- 
taries are plains and meadows so level that the eye can hardly dis- 
cover the smallest declination in their surface. But by far the great- 
er part of the valley, probably nine tenths, presents a surface perpetu- 
ally changing, rising and falling with every variety of steepness, from 
the most gentle undulations, to abrupt mountains and perpendicular 
cliffs. These inequalities and changes of form are not to be ascribed 
