Vlll 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 nine 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 inland 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 



