148 H. L. FAIRCHILD 
which is about eighty feet higher. The most northern point of 
the high plateau is at Batavia, on nearly the same parallel as 
the Mud pond, where the drumloidal and morainic drift capping 
is something over 900 feet. 
While the summits of the kame hills are 100 feet above the 
surrounding drumloids the enclosed swamp valley is nearly 100 
feet lower than the drumloid region. It has not been deter- 
mined whether the swamp is floored by rock or by impervious 
drift. 
The topography of the hills is of pronounced knob and basin 
type and strikingly in contrast with the neighboring drumloids. 
(See Fig. 6.) They are conical, mammillary, billowy, enclosing 
numerous basins and deep kettles. The hills have nearly 
~ escaped the leveling action of the Warren waters, the summits 
lying between the two erosion planes. However, the lower, 700 
feet, plane shows upon the western hills. 
The drainage from the ponds and enclosed valley is immedi- 
ately southward, forming the head of the Irondequoit creek. 
After passing Mendon Center the stream swings eastward to 
Fishers and then northward to Irondequoit bay. From the 
borders of the kame area the drainage is radial in all directions. 
The altitude of the southern part of the overwash sand and 
silt is about 600 to 610 feet (aneroid). 
Lakes.—Vhe location, drainage and relative size of the four 
lakes are shown in the accompanying sketch. The “ Big pond” 
lying most northerly and the head of drainage, has an area of 
about 100 acres, and a depth of only about eight feet. The 
‘Harris pond” lies nearly surrounded by the heavy drift on the 
east side of the valley. It is only a few acres in extent but is 
said to have a depth of twenty-four feet. ‘‘Deep pond” is 
mostly shallow but is said to be thirty-four feet at the deepest 
place Biewpond sand Mud pond) sareysirallow-aiihe smi 
gins of the lakes are mostly swampy, but much of the valley 
bottom between the lakes is tilled land. 
Composition and structure —The kame hills are mostly pasture 
land or under cultivation. Very few exposures have been made 
