532 
BULIvETIN OF THE BUREAU OF FISHERIES. 
with which most of the work was done, is still in good condition. It was recently 
calibrated and found accurate. There is every reason to believe that the earlier instru- 
ment was equally good. The soundings were well placed and the position of each was 
controlled by transit instruments on shore and a sextant in the boats. Every care, 
therefore, was used to secure accuracy in detail. 
All of the under-water contours, both for the working maps and for the engraver, 
were drawn by Mr. L. S. Smith, associate professor of topographic engineering in the 
University of Wisconsin. 
TOPOGRAPHY AND HYDROGRAPHY OF THE FINGER LAKES DISTRICT. 
GENERAL ACCOUNT. 
In the central part of the State of New York lies a plateau composed of nearly 
horizontal strata of soft Devonian shales and sandstones, whose highest points reach 
an elevation of about 700 meters (2,300 feet) above the sea. That part of this region 
with which this paper deals is known as the Finger Lakes district. (See sketch map, 
fig. I.) It is bounded on the west by the valley of the Genesee River, which extends 
completely across the State. From this it extends about 140 kilometers (84 miles) 
eastward to the eastern tributaries of the Seneca River. It occupies the northern 
slopes of this plateau, with a maximum breadth of about 70 kilometers (40 miles). 
The meridian of 77° lies close to the center of the district, and it is bounded on the north 
by latitude 43°. 
Lake Ontario lies about 40 kilometers (25 miles) to the north of this region. The 
district between the base of the plateau and Lake Ontario is deeply buried in drift 
whose surface is shaped into innumerable drumlins. The surface of the plateau itself 
bears but little drift. Its hills have been little eroded, but its valleys have been 
smoothed, widened, and deepened by the continental glacier. 
The waters of the western one-fifth of this district drain into Lake Ontario by the 
Genesee River, which flows almost directly north to the lake. Across the north front 
of the remainder of the district flows the Seneca River, which has its origin in Seneca 
Lake, but is continued to the west by the Clyde River and the creeks that constitute 
the headwaters of that stream. The two rivers have a course in general almost directly 
east for 100 kilometers (60 miles) flowing between the base of the plateau region and 
the drift-covered region to the north. The stream has found out for itself a course, 
twisting about among the groups of drumlins in an imperfectly developed valley, which 
offers very little slope for its flow, so that large marshes are developed. This valley 
has furnished the course for the Erie Canal. The Seneca River empties into the Oswego 
River, which flows nearly north, directly into Lake Ontario. 
The chief tributaries of the Clyde and Seneca Rivers come from the plateau to the 
south, which is deeply trenched by their valleys. Some nine principal valleys extend 
southward into the highlands for a distance varying from 40 kilometers or less at the 
eastern and western limits to nearly 100 kilometers in the center. These valleys are 
nearly parallel. (See fig. i.) Those in the center extend almost exactly from north to 
south. Those to the east diverge eastward and those to the west have a westward 
inclination. 
