16 TRANSACTIONS OF THE [oct. 15, 
In some instances this eccentricity may doubtless be accounted 
for by local land slips, but in other cases I am inclined to think 
that an east dip on the west side of a harbor or a west dip on 
the east side may be explained on the theory advocated by F. 
J. H. Merril,* that these inlets are due to tongues of ice which 
were either in advance of or plowed deeper than the main mass. 
In such a case there would bea side thrust or squeeze along 
each of these inlets, which would produce the dips noted, in 
opposition to the generally prevailing north and south dips. 
On the north shore of Gardiner’s Island may also be seen exam- 
ples of east and west dips in the clay strata. (See Fig. 5.) 
Fic. 5. DistortTED CLAys, NorTH SIDE OF GARDINER’S ISLAND. 
Suchan explanation would be not only in harmony with the theory 
of ice action in general, but also a special argument in favor of 
the formation of these harbors by the same agency. 
I do not know whether the competency of ice to produce the 
effects noted will be questioned, but the distorting effects of 
even small superficial loads on clay strata, such as trees and 
bowlders, has been recognized, and the pronounced effects of 
comparatively weak thrusts upon yeilding strata are too well 
known to need extensive comment. It may perhaps be not out 
of place, however, to recall the prominent example of the land- 
slide which occurred at Brantford, Ontario, April 15, 1884, by 
which the Erie clay was raised into truncated, anticlinal folds 
by the forward movement of the displaced mass at the limit of 
its furthest line of advancement. A brief account of the 
* “On the Geology of Long Island,”’ . c., 359. 
