MAP AND GENERAL FEATURES OF THE REGION. 175 
My study of Jamesville lake began soon after I came to Syracuse, in 
1895. Since then I have spent considerable time, as occasion permitted, 
in the study of the topography of the lake and its vicinity. In order to 
represent the somewhat complex features of this region more clearly I 
constructed a topographic map of the lake and adjacent areas on the 
scale of 1:1500, which in reduced form faces page 174, as plate 12, and 
have reproduced photographs * of several of the localities referred to 
thereon (see plates 15 and 14). 
The distances noted on the map were for the most part paced (a few 
were chained) and the heights were taken from aneroid readings with 
datum level some distance away, and are therefore only approximately 
correct. The broken lines are not contour lines, but are intended to rep- 
resent approximately. by their varying distances apart the steepness of 
slopes. By using a large compass and pacing most of the distances twice, 
the map has been made, it is believed, fairly accurate in its main features. 
Before entering on a description of the lake and its immediate vicinity 
it will be desirable to give some account of the region which constitutes 
its larger environment. 
GENERAL FRATURES OF THE REGION 
Jamesville lake lies between two of the main valleys which dissect in 
this region the New York plateau in a general north-and-south direction. 
The valley to the west, which leads past Syracuse, is occupied by the 
Onondaga creek. The one to the east, which leads past Jamesville, is 
occupied by Butternut creek. They run approximately parallel to 
each other, from 33 to 43 miles apart, across the plateau northward, di- 
verging rapidly after they leave it. They are broad, well defined val- 
leys, and were plainly a part of the preglacial drainage system of the 
region, as their floors are filled deeply with glacial debris. This debris 
was not sufficient in amount, however, to entirely fill and obliterate the 
old valley, whose sides, composed of Devonian strata, still rise 200 and 
300 feet above the present valley floor. The plateau block or spur sep- 
arating the valleys of Onondaga and Butternut creeks is also covered 
with glacial debris, from a few to more than a hundred feet in thickness. 
For several miles south of Syracuse the glacial deposit capping the pla- 
teau takes the form of well developed drurlins, whose long axes have a 
- general northwest-and-southeast direction, and whose bases merge to- 
gether so that the country rock is almost everywhere concealed from sight. 
The conditions so far described are thus seen to be comparatively sim- 
ple and easy of interpretation. We have a plateau composed of nearly 
* For these photographs I am indebted to the kindness of Mr C, E, Cummings, 
