REPORT OF THE DIRECTOR, 1922 159 
As the inquiry was pushed into various critical regions the 
ice front became more and more fictitious and the evidence of 
wide areas of stagnant ice more and more convincing. Delay 
in the publication of scientific papers by the State of New York 
has afforded opportunity for testing the relative values of the 
two conceptions (the ice-front withdrawal and the stagnated 
glacier melting im situ) as aids in the interpretation of topography, 
in many widely separated localities in eastern New York. ‘The 
hypothesis of a general condition of stagnation during the abla- 
tion of the Wisconsin ice is, therefore, advanced with a corre- 
spondingly greater degree of confidence, in that a general con- 
dition demands for its explanation a general cause. 
Briefly stated, the hypothesis is this: 
That part of the glacier which had been pushed beyond the 
mountain barriers south of the St Lawrence river from the 
Adirondacks to Maine, became stagnant almost, if not quite, at 
its maximum extension and never regained its motion. 
This is recognized as an overstatement but the necessary 
qualifications are easily made and, for the moment, may be 
ignored. After allowance has been made for local “streaming ” 
through the field of dead ice and for at least one possible thrust 
of live ice into it, (see page 168) it remains true that stagnant ice 
and the associated waters-of-melting played the principal roles 
in shaping the recessional drift. 
The high relief and the general topographic relations of the 
area covered by this part of the ice sheet offered more favorable 
conditions for early stagnation than the lake basins and smoother 
surfaces found further west. So that, if any general cause were 
to operate to deprive the whole glacier of a part of its pressure 
head, this part would be more likely to respond by stagnating 
than, for example, the Erie Lobe in Ohio and Indiana. That a 
general cause did so operate we know. At the climax of the ice 
burden, the lithosphere subsided under the glacier; the transfer 
of material in the zone of flow* was radially outward from under 
*The idea expressed by this term has been variously conceived. The 
use of a name by which to designate a condition of the deep-seated rocks, 
such as asthenosphere and the like, seems to imply the existence of a zone 
or layer beneath the rigid exterior, which is more or less sharply marked 
off from what is above and what is below. There is probably no such 
demarkation; rather, the fact is to be understood as follows: On each 
radius of the earth there is a point or section where the balance between 
pressure and temperature is nearest to the critical relation where fusion 
occurs. If all these points or sections be thought of as constituting a 
