37 ° 
Frank Carney 
The only condition insisted upon in this form of the constructional 
type of ridge is that the coincidence of such a stream course and 
one or more crevasses would give the requisite relation of ice and 
a loaded stream to produce the accumulation of debris noted in 
these ridges. 
The destructional ridge results from the erosional Work of ice- 
front streams whose courses have been shifted either by a slight 
advance of the ice or by a barrier derived from a localized greater 
load of debris in the ice. The suggestion as to a localized condi- 
tion of debris is found in the reports^^ of Chamberlin & Salisbury’s 
studies in Greenland. 
(4) Isolated Hillocks. A featureless outwash plain is some- 
times most surprisingly interrupted by a lone hill of drift often 
so symmetrical in development as to suggest artificial origin. I 
have also seen a few such hills on the upland near the east side of 
the valley between Locke and Groton. They consist of both till 
and washed deposits, the latter being more common. As to 
origin, it seems reasonable that these lone hills of drift may mark 
the brief continuance of factors which would produce, if given 
more time, some of the ridges described in the preceding section; 
subdued moulin work might make such hills. It is not forgotten 
that a considerable degree of symmetry might in time be developed 
by normal subaerial erosion on an original mass of drift less 
regular in outline. The fact, however, that no constant condi- 
tion as to water-laid or ice-laid drift is prevalent in these hills 
precludes our interpreting them as less well developed kames. 
(5) Kame Areas. Hillocky areas of prevailingly stratified 
drift are formed in valleys either at the margin of the ice or back 
aways from the front as the ice becomes rather stagnant. Such 
areas are noted in the triangular plains that mark the union of 
mature valleys. They are likewise noted along the valley walls 
in the intervals between loops of drift. This type of drift in which 
washed material predominates has also been observed in the 
higher -^rea between valleys. The promiscuous location of these 
kame areas tends to eliminate a topographic control as the sole 
factor in their genesis, though it is evident that more of such drift 
is found in some topographic relations than in others. 
The most extensive kame-area of this sheet is found east and 
Geology, vol. i, (1904), pp. 296-97. 
