LAKES. 
407 
lateral, and of very modern origin; emerging at Penn-Yan, and excavating a channel in the 
lower part of the Portage group, the whole of the Genesee slate, and about two hundred feet 
of the Hamilton group, it flows into Seneca lake at Dresden. The descent along this outlet 
is two hundred and seventy-one feet. 
Canandaigua lake , the fourth in the series, occupies a position in the rocks of the 
Hamilton and Portage groups, extending northward almost to the Corniferous limestone. Its 
length is about fourteen miles, and it has a breadth of from one to two miles. Towards its 
northern end it is becoming shallow, and aquatic plants and grasses rise above the surface of 
the water. There is also an extensive marsh at its southern extremity. This is the most 
westerly lake that flows into the Oswego river. Its outlet is northward for several miles ; 
passing over the Corniferous limestone, and then turning eastward, it excavates a channel 
through marl and gypsum beds of the Onondaga salt group. 
The three lakes, Honeoye, Canadice and Hemlock, lie in deep gorges in the rocks of the 
Portage group. The first opens northward into a beautiful valley, along which the waters of 
its outlet flow. The outlets of the other two unite, and after a circuitous route join that of 
the Honeoye, which flows into the Genesee river. The length of the two largest of these 
lakes is about six miles, and of Canadice about three miles. 
The Conesus lake, of which a sketch is presented at the head of the chapter, is one of 
the most beautiful sheets of water in the district. It is situated in rocks above the Hamilton 
group, and presents gently sloping banks to the water’s edge, covered with a fine forest of 
oak, hickory, etc., except where the hand of industry has replaced them with cultivated fields 
and meadows. Its length is about nine miles, with a width of one mile. Its depth does 
not exceed sixty feet, and for the greater part is much less. Its outlet passes over rocks of 
the Hamilton group, the Marcellus shale, the Corniferous and Onondaga limestone. 
West of the Genesee valley, we find several small lakes in the higher rocks, and some of 
them at great elevations above the ocean. The principal are Silver, Java, Bear, Cassadaga 
and Chautauque lakes. These are not situated in the well defined north and south valleys, 
like those previously enumerated. Chautauque lake is the only one of any considerable mag¬ 
nitude. It is eighteen miles long, and contains sixteen thousand acres. 
All the last named lakes, with the exception of Silver lake, flow into the Allegany, 
mingling their waters with the ocean in the Gulf of Mexico. 
Of the chain of great lakes, we have to notice two as coming within the district: Lake 
Ontario being the northern boundary, and Lake Erie, with the Niagara river, the western 
boundary. They form two of those great depressions in the immense basin of the St. Law¬ 
rence which are occupied by these seas of fresh water. The length of this basin or valley, 
from the Gulf of St. Lawrence to near the sources of the Mississippi where it commences, is 
almost two thousand miles ; and the whole area has been estimated at more than five hundred 
thousand square miles, of which from eighty thousand to ninety thousand are covered with 
water.* 
* The area of this valley, and the surface of the water, are differently estimated by different individuals. 
