Champlain eras in New England. 199 
one point, the height of the icy plateau in which the glacier- 
flow over New England had its head, (treated in vol. ii of this 
Journal, p. 824, 1871,) I give additional observations with 
a modification of my former conclusion. 
nad transportation by moving waters and floating ice. 
carry a boulder one hundred miles, the distance from t 
northern boundary of Massachusetts to New Haven, Ct.; and 
how many times ‘one hundred miles were passed over by the 
Ice has not yet been deciphered. The progress of the melting 
otten a more or less perfect conformity to the course of the 
valley; showing that the movement of the lower part of the 
glacier was determined, in some degree, by the slopes of the 
surface beneath—just as thick pitch, descending a gently-inclined 
oard that has large oblique furrows in its surface, would follow 
the general slope of the board, but have a part below diverted 
y the furrows. The direction of movement was determined 
by the general slope of the upper surface of the glacier; and this 
depended on the Sisiriontion of precipitation and temperature, 
and the position of the region of freest discharge, as well as 
the general slope of the land ; but the influence of the valleys 
ag was the same, whichever of these causes was predomi- 
nan 
IV. Since the glacier was spread widely over the country 
and had no overhanging rocky walls or peaks, its stones and 
earth must have been gathered into its lower part where it lay 
in contact with the earth’s surface. It brought to the New 
aven region masses of trap, of all sizes, from small peb- 
bles to boulders of 1,000 tons, and these must have been taken 
Up for transportation from the trap ridges of the Connecticut 
valley, nearly all of which are under 1,000 feet in height above 
the sea It also brought 3 of sandstone from the lower 
hills or plains adjoining: and from veins in the roe dug 
out pieces of native copper, which were dropped on paces! ; 
one such, found within two years past, a few miles north o 
