1 
180 BE. C. QUEREAU—JAMESVILLE LAKE, NEW YORK. 
smaller one is of lesser diameter and about 100 feet deep. They are 
separated by a ridge which rises like a partition about 50 feet above the 
bottom of the deeper hole. Farther to the north are a considerable 
number of other similar depressions of all sizes, from very small ones up 
to those which are nearly as large as those just described. To the south- 
east of the lake also are two depressions of considerable size, as shown 
upon the accompanying map. 
These peculiar depressions are all excavated in Lower Helderberg lime- 
stone, though the top of enclosing wall is, in the case of the more west- 
erly depressions, capped by harder layers of Oriskany sandstone and 
Corniferous limestone. A noteworthy feature of these depressions is the 
fact that they lie in the path of one or other of the well marked channels 
which traverse this region in a general east-and-west direction. 
CHANNELS 
Although Jamesville gorge proper begins only 200 or 300 feet west of 
the lake, plain traces of an old watercourse (see plate 12, numerals 1, 2, 
3, 4) can be followed westward for a mile or more, and less plainly nearly 
to Onondaga valley. The contrast between the shallow and weakly dif- 
ferentiated courses to the west and the deep gorges east of Jamesville lake 
is striking and is characteristic of the other channels as well. The reason 
for this is not entirely clear, but it seems to be related to the character of 
the rock formation which dips gently to the west, so that in the region of 
the deep channels we have softer (Lower Helderberg) rocks capped by 
harder (Oriskany-Corniferous) beds, while to the west, where the chan- 
nels are shallow, the only rocks exposed are hard ones. 
The kettle-like depressions described lie in the eastern part of the 
region—that is, in the region of the deeper channels. They he with one 
or two exceptions in the course of these channels. Their upstream or 
western side is in all the larger ones a high, steep wall of rock. The 
downstream side is low, the enclosing wall being removed on this side 
down nearly to a level with the bottom of the depression. ‘The largest 
depressions are as a rule found in the course of the largest channel. This 
is true of the Jamesville lake depression and its gorge. 
TERRACES 
Several of the channels show more or less well developed terraces 
along their sides, but this feature is best studied in the Jamesville gorge. 
To the west of Jamesville lake, where the channel is broad and shallow, 
the terraces are correspondingly low and broad. From the lake east- 
ward down the gorge proper the terraces are very strikingly developed. 
They are sharply outlined, high, particularly at the eastern end, and line 
