:>«s<) The American Geologist. November, 1893 
of ice, the remnants and outliers of the vanishing ice-sheet. 
The same agency has been appealed to in the case of the nu- 
merous lakelets and ponds, with steep sides, which interrupt 
the surface of glacial sand-plains, as in the district of south- 
ern New England. This explanation is satisfactory for all 
the examples which have been studied, and it now seems de- 
sirable to go a step further and to inquire into the dimensions 
of these outliers of the ice. 
The length and breadth of the detached ice-masses are ap- 
proximately indicated by the corresponding dimensions of the 
existing depressions. The level of the bottom of the ice-block, 
below the surface of the completed deposit about it, is equal 
to the depth of the depression plus the depth of material 
coming to rest upon the bottom on the melting of the ice, plus 
that which has been washed or blown in during the post- 
glacial epoch. 
The question is whether the plain or other glacial deposit 
originally extended over the mass of ice, as some authors have 
implied, thus burying the ice, or whether the outlier still rose 
above the deposit when deposition about it had practically 
ceased. In the following discussion I hope to show that both 
of these conditions are manifested in particular instances. 
The structure of those stratified deposits which covered 
basal remnants of ]the ice-sheet affords of itself, by the dis- 
turbed bedding, proof of the once underlying ice. The typ- 
ical kettle-holes and the irregular, inosculating depressions in 
many kame-fields fall largely in this group, where the thick- 
ness of the ice may not at -the time of completed deposition 
have exceeded one hundred feet, if in most cases it did not 
fall far short of this estimate. 
An outlier, however, may have risen high above the depos- 
its at its base and yet not have been deeply imbedded in the 
drift. Setting aside these possible cases, I propose to deal 
only with those instances in which the ice occluded a depth 
of sediment sufficient to leave a depression upon its liquefac- 
tion. The point is to distinguish a depression of this nature 
from one of the kind previously described, particularly when 
the cavity is at present the seat of a body of standing water. 
There seems to me a solution of this question resting on 
the assumption that, if the mass of ice rose high above the 
