vill PREFACE. 
Lake Ontario into the Gulf of St. Lawrence, and on the other into the Delaware 
and Chesapeake bays, and into the Gulf of Mexico. The central portion of this 
district is a level table land, rising in its southern parts into elevations of from a 
thousand to twelve hundred feet above tide, and abruptly subsiding on its western 
borders to the level of the great lakes. In the western part, we have the Cat- 
taraugus and Tonawanda streams pouring into Lake Erie and Niagara river ; 
the sources of the Allegany river ; one of the branches of the Ohio, itself a tribu- 
tary to the Mississippi; and another branch of the Allegany takes its rise from 
Chautauque lake, a sheet of water sixteen miles in length, 1291 feet above tide, 
and 726 above Lake Erie. Eastward of these is the Genesee river, which, 
taking its rise in Pennsylvania, crosses the whole district in a north direction, and 
empties into Lake Ontario. As we proceed eastwardly, we cross successively, in 
the southern portions of this district, the Canisteo, Conhocton, Chenango, and 
great western branch or principal source of the Susquehannah, which takes its 
rise in the Otsego lake, a sheet of water nme miles long, with a breadth varying 
from three quarters of a mile to three miles. The central portions of this district 
are occupied by a series of ten to twelve lakes, stretching generally to north and 
south, varying from fifteen to thirty-eight miles in length; all discharging them- 
selves by one common outlet, the Oswego river, into Lake Ontario. On its ex- 
tremely eastern border rises the Mohawk, a tributary of the Hudson, which con- 
nects it zoologically with the Hudson river district. The great mland seas of 
Erie and Ontario, the one two hundred and seventy miles in length, with a 
breadth from twenty to fifty miles ; and the other one hundred and ninety miles, 
with an average breadth of forty miles, exercise a great influence on its climate 
and consequent zoological character. The surface of Lake Erie, which is three 
hundred and thirty-four feet above Lake Ontario, discharges its waters through 
the rapids and falls of Niagara river, into that lake, within a distance of thirty-six 
miles. This entire district is exceedingly fertile, and is covered by a vigorous 
growth of forest trees in the uncultivated portions. Without entering into details 
which would find a more appropriate place in a topographical survey, it will be 
perceived, that while on the one hand the vicinity of such large masses of water 
must ameliorate its climate, its fertile soil irrigated by so many streams will fur- 
nish the means of subsistence to numerous species of animals. It is zoologically 
connected by its valleys and water courses with the great basin of the St. Law- 
rence, and we accordingly find in this district animals common to both, although 
