372 J.D. Dana—The Flood of Connecticut River Valley. 
with till the glacier-buried land. But, meinen ap ncd when the 
rising streams had volume enough to make the lower range of 
terraces, along the valleys, the roofs of ‘hie, tunnels were prob- 
ably, for the most part, gone. The ice still lay over the land, 
covering deeply the hills and mountains, but the wide channel- 
ways were open to the day. Evidence of this is afforded by 
the fact that these lower terraces, like the higher, are free, with 
rare exceptions, from deposits or droppings of till or of bowlders, 
su wou ave come from an overhanging glacier. But 
outside of me terrace plains, up the hill slopes wherever the 
ice still remained in force, the till may have continued to fall, 
adding later to earlier till. Other evidence that the streams, as 
the floods rose and terracing went forward, were free from ice 
overhead is afforded by the Lake Champlain and St. Lawrence 
valleys. The shell-bearing sea-beach deposits at Montreal 
and on Lake Champlain could hardly have been formed from 
a cae rowth of mollusks and other marine species while 
the glacier lay over the whole region to the Gulf, a distance 
from Montreal of 500 miles. Whales (Beluga Vermontana, re- 
sembling much B. leucas Gray), and seals, inhabitants of the 
ays of Arctic coasts, — ever have made their way be- 
neath such a cover of ice to Lake Champlain, a region also 
500 miles and the Lake Champlain region were free of ice, 
this may also Lig been true of the larger lige of New 
England and the 
ec. It follows fon the existence of a cut across the glacier 
—_ the St. Lawrence valley, from Lake Ontario to the Ocean, 
er 500 miles from east to west, and north of all New Eng: 
land, that at the time of highest ‘flood New En gland was not 
receiving additions to its ice through the anal movement 
of the great northern g 
d. The sapocrreauiae valley, at the time of maximum flood, 
have reached the amount deduced above—a cubic mile per rae 
* Tt will be observed that such conditions were well fitted, especially toward 
the mountains or in 7 region “of the upper sub-glacial portions of the tribu- 
streams, to pi e and set afloat masses of ice laden h till, to float 
do ibutary to ‘the Connecticut—a kind of work that mu ae have 
early in the era of melting. Reaching the wide borders or flood-grounds of this 
m 
ae Save helped to make the coarse gravel and cobble-stone beds which, in 
