259 
Compound deltas built at several different levels are numerous in the 
Finger lake region. Coy Glen delta near Ithaca, a fine specimen of the 
type, rises from the Cayuga valley to a height of 700 feet like a giant stair- 
case of seven steep, convex risers and as many flat treads, each of which 
has been evenly bisected by the stream. Such deltas are formed in waters 
the level of which is alternately standing and falling, the upper step being 
the oldest. They may be distinguished as step deltas. 
The delta above Naples rises 400 feet and has a basal periphery of 
more than two miles. (Fig. 8). Seven levels are distinguishable, of which 
the upper three are the most conspicuous. The greater part of its mass 
rl = ¢ 
Fig. 4. Pitted Surface of Morainal Delta. 
was brought by a stream which flowed out of the Honeoye valley from the 
west and was the outlet of the glacial Honeoye Lake. Streams which flow 
out of lakes cannot, as a rule, have sufficient load to build large deltas, 
and the question at once arises, how could the outlet of a lake build one 
in this case? Its construction was not a matter of a brief period but con- 
tinued through the whole iife history of the Naples-Middlesex glacial lake, 
into which the stream emptied. The presence of this delta is evidence, 
so far as it goes, that during that period no lake existed in the Honeoye 
valley. The area of the land which could have been drained to this delta 
is insignificant, and we are apparently forced to the conclusion that it was 
built by drainage from a drift-loaded ice mass. This inference is sustained 
