136 Vale Why SIAR CIEHHLIO) 
beyond which it is probably buried under the lofty sand hills 
south of the creek. However, it can probably be identified south 
of the canal, at the south end of the canal embankment, ina 
mass of cemented, dark red Medina gravel which is similar in 
appearance to an exposure in the esker at the north end of the 
embankment. About 30 feet in thickness is shown of this 
cemented gravel, of which, by estimate, from one-half to three- 
fourths is red Medina. This occurs at the canal level, 461 feet. 
Similar dark red, cemented gravels occur at other localities ; one 
and one-half miles south near the Rand powder mill; at Fishers 
station; in the sand cut near Allen creek at the extreme north- 
west point of the preserved kame area; also near the bottom of 
the Irondequoit gorge. It is suggested that these masses of 
‘cemented Medina gravels found in the distinct esker ridge and 
at different points in excavations northward and southward indi- 
cate the deposit of subglacial streams deriving their burden 
chiefly from the Ontario excavation in the Medina, which esker 
deposits have been mostly buried under the later sands deposited 
in front of the retreating ice. 
Lakes.—South of Bushnells basin two lakelets exist, locally 
called ‘‘ Bullhead pond” and “Lily pond.’ They are about 
one-fourth of a mile apart. The ‘Lily pond” is said to be shal- 
low, the other deeper and more surrounded by sand hills. These 
are somewhat below the canal altitude 461 feet. 
Another lakelet called ‘‘Crossman pond,” or ‘Cedar pond,” 
lies one-fourth mile north of Woolston hill, by the side of the 
Ketchum road. It has an area of about two acres, with a reported 
depth of 60 feet. The altitude is about 520 feet (aneroid). 
Between Pittsford and Penfield are at least five pools and one 
swamp, lying in depressions in the billowy sand. 
Composition and structure.—TYhe surface of the northern portion 
of the area is chiefly a fine yellow sand. Below the Iroquois 
level this sand is much affected by the winds, and the billowy 
surface may be wholly due to eolian action. 
The cutting by the railroad near Allen creek exposes about 
70 feet of sand, inclosing a few lenses of gravel, and some angu- 
