A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 545 
of the lake. There are, therefore, no deltas built into the lake, but the steep wall of 
the valley rises immediately from the water on both sides of the lake. 
The outlet of Hemlock Lake is controlled by a dam, which may raise the water to a 
height of about 1.6 meters (5 feet) above its natural level. No h37drographic survey 
has been made of the lake. This is the more regrettable since the form and topography 
of the lake adapt it admirably to the study of the temperature seiche. Not only is 
the lake straight and of uniform breadth and depth, but the shape and depth of the 
valley are such that all winds that affect the water must blow parallel to the long axis 
of the lake. 
The maximum depth of the lake as found by us was 27.5 meters (90 feet), and this 
was said by the officials of the Rochester water department to be the deepest water 
of the lake. The observations on Hemlock Lake were made near the middle of its 
length. 
The transparency in 1910 was 4.7 meters. 
Fig. 4. — Hydrographic map of Canadice Lake. From survey by city of Rochester department of water supply. Contour 
interval, 25 feet. Scale, about i: 64,000. Note the steep sides and flat bottom of the lake. The outlet of the lake is at the 
north end. 
Canadice Lake (fig. 4) is the smallest of the lakes which we visited and the only 
lake of the Genesee Basin which has had a hydrographic survey. This was done with 
great care by the department of water supply of the city of Rochester, whose officials 
were so kind as to place their maps at our disposal. 
The valley of Canadice Lake is a simple trough, with smooth steep walls, almost 
exactly like the valley of Hemlock Lake, though the eastern slopes of Canadice Valley 
carry somewhat larger streams and have cut somewhat deeper into its sides. The slopes 
under water are even steeper than those above it and the ratio between the maximum 
and the mean depth of the lake (see table i) is considerably greater than for any other 
lake. More than three-fourths of the maximum depth must be passed before the plane 
is reached whose area is one-half that of the surface. In correspondence with this 
relatively great depth and volume Canadice Lake shows a biological character more 
resembling that of the larger lakes than does any other of the smaller lakes. It carries 
a good deal of oxygen to the bottom. The temperature of the deep water is low in 
spite of the fact that its total gains of heat are higher than would be expected from its 
area. 
The lake was visited once and observations were made near the north end. The 
transparency of the lake was 4 meters. 
For the details of the hydrography of the lake, see page 597. 
