204 Tlie American Geologist April isoo 
kame as a dam. Within half a mile north of the Cartersville 
kame a diffused deposit of sand begins and soon assumes the 
shape of a massive and well defined ridge which extends north- 
ward two miles and ends abruptly at the bank of Allen's 
creek. 
Perhaps the most remarkable feature of the region is the 
so-called "sugar loaves." They are isolated, conical, sand hills, 
rising from the bottom of the Irondequoit gorge to a hight 
level with the top of its walls or nearly so. Two small ones 
stand near the head and a group of four large ones three miles 
beloAv. The latter are islands surrounded by channels of the 
stream. The most symmetrical one is an almost perfect cone 
20 rods in diameter and 150 feet high. Such sharpness of out- 
line and high angle of slope in a pile of sand is rendered some- 
what less marvellous by the fact that the cones are covered by 
a growth of pine trees and deciduous shrubs. How these 
forms originated is an interesting and difficult question, but 
certain features of the surrounding region seem to throw light 
upon it. The sugar loaves evidently form a part of the Iron- 
dequoit kame system, the larger group being a continuation in 
a direct line of the above described kames. That all are rem- 
nants of one originally continuous kame is an assumption 
warranted by their structure and position. Again, two of the 
cones are almost connected with the east wall of the gorge by 
curved ridges of the same material, now no more than half as 
high and cut off from the cones by channels of the river. In 
short they are unusual if not unique forms resulting from the 
general laws of drift erosion, here acting under peculiar con- 
ditions. In the washing out of the drift from the gorge paral- 
lel tributaries left high narrow ridges between them, while at 
the same time shifting channels of the main stream, at first 
flowing at a much higher level than now, cut a cone off" from 
the end of each ridge. They are analogous to the buttes, mon- 
uments and other erosion forms of the Rocky Mountain plateau. 
The whole region is extremely suggestive of questions as to 
the origin of the peculiar forms of knobby drift, and the laws, 
processes and limitations of drift erosion, problems which do 
not seem as vet to have been adequately considered. The 
Irondequoit cones seem to the writer to stand as dumb but 
eloquent protests against any theory which would assign a 
