Glacial Lakes. — V phani. 227 
passing far above the limit of the fossiliferous marine deposits 
in the southern part of the basin of lake Champlain. 
Northward from the vicinity of the city of New York the 
land was then depressed and has since been elevated, as shown 
by the hights of the uppermost shore and deltas of this lake 
Hudson-Champlain, which, as determined by Davis, are 180 
feet above the sea at West Point, fifty-two miles north from the 
mouth of the Hudson at the Narrows ; 275 feet at Catskill, 
about no miles from the Narrows; and 325 to 340 feet in and 
near Albany and Schenectady, at 145 to 160 miles. The pres- 
ent ascent of the originally level shore is thus 160 feet in about 
ioo miles. 
A early the same gradient of differential elevation, but some- 
what increased, continues north to Chesterfield, N. Y., on the 
west side of lake Champlain opposite to Burlington, where 
Baldwin reports a series of eight beaches referable to the suc- 
cessive water levels of lake Hudson-Champlain, lake St. Law- 
rence, and the sea in the Champlain basin, their hights above 
the sea level of today being 550 feet, 530, 470, 423, 386, 365, 
335, and 290 feet. This locality is 270 miles north from the 
Narrows ; and the lowest shore in the series is nearly .200 feet 
above lake Champlain, which has a mean level of 97 feet above 
the sea, with a maximum depth of 402 feet. The lower four 
of these beaches belonged to the Champlain arm of the enlarged 
Gulf of St. Lawrence, as shown by the hight of its sand deltas 
and associated fossiliferous clays ; but the four higher beaches 
represent stages of the two earlier glacial lakes. 
A large delta plain, which I examined, composed of hori- 
zontally bedded sand and gravel, was formed at the earliest and 
highest level of the lake Hudson-Champlain around the town 
of Saratoga Springs and for a few miles southward, having a 
hight of about 375 to 390 feet above the sea. Next to the north- 
east, for about five miles, at the same or a slightly greater al- 
titude, are abundant short esker ridges of coarser gravel, ten 
to thirty feet high above the intervening hollows. Here the 
waning ice-sheet supplied abundant englacial and finally super- 
glacial drift to the streams of its melting and of attendant rains, 
where confluent glacial currents and slopes of the ice surface 
met from the northeast and northwest. 
