LEE TMI ST AINGGCELACTAL, LAKTE DE IALAS 593 
material of the low ridge at the notch opening into the basin is 
more like till than it is like gravel. Water movement probably 
had some part in the formation of the ridges, the currents 
sweeping about the half buried ice-block. 
If the basin were due to deficient filling obviously the inner 
slopes should consist of finer material dropped by the weakened 
Kettle in Delta at Potter, N. Y. View of deepest part looking north. 
currents. Such isnot the case. The materials are stony, and © 
even large boulders occur. The writer observed no boulders 
which might not possibly have been rolled by powerful currents, 
although the much more reasonable explanation would attribute 
them to ice transportation. The owner of the larger part of the 
basin said that blocks of stone exist in the basin “as large as a 
team could haul.” 
The existence of elevated portions or isolated areas some- 
what above the general plateau level might be regarded as due 
to erosion of the surrounding area, but seem more reasonably 
