The Retreat of the Glacier. 371 
loss were 340°6 cubic miles, the same work would have taken 
about 24 years. 
8,215 cubic miles of ice are equal to the part of the glacier 
estimated to have occupied the drainage-area of the Connecti- 
cut at the time of maximum ic 
Supposing the above numbers : approximately correct, we are 
still far from a knowledge of the time taken during sto 
flood for the disappearance of the ice from the ieee in 
order to np a conclusion it is necessary to know 
approximate amount of ice that was still in the 
valley ieee the epoch of maximum flood was reached, the 
estimate rales eing the amount at the time of maximum ice. 
(2.) Whether the southward movement of the great northern 
glacier still continued, and was adding to the amount of ice. 
(3.) What was the amount of ice contributed at that time 
by local glaciers within, or on the borders of, the drainage-area, 
which glaciers used some of the precipitation to make ice for 
melting 
(4.) “Whether the melting, instead of continuing on uni- 
formly, had its years or periods of ats ase n. 
(5.) Whether the time of maximum flood was not quickly 
passed, even in one, two or age years, so that the discharge 
of the river was at its highest stage only for a very short time 
and rapidly declined to some limit, Sgt thereby, both the 
rate a flow and the amount of wate 
doubts on points so jin pornat this time-question must 
be set ts as of impossible solution 
But while a definite answer is not to be expected, we may 
see reason for be yer 2th general inferences. 
e of maximum flood the ice was not lying 
along the ccireae of te valley producing the river by its 
ual melting, and retreating eae as the river elongated in 
that direction 
The amount of water flowing off with a selegre of three or 
_ four or more miles an hour, making the great flood, was too 
vast to have been generated from a eanekal body of ice in 
the valley. 
b. If, as Greenland facts authorize us to believe, sub-glacial 
rivers of large size and energy were a universal feature of the 
Am, Jou ete = —THIRD salen, Vou. XXIII, No. 187.—Mary, 
