PREFACE. Vll 



Italy, the south of France, and the northern parts of Spain ; yet from the well 

 established fact of the more southerly position of the isothermal lines on the 

 western shores of the Atlantic, its mean annual temperature cannot be compared 

 with that of the above mentioned countries, but rather with those lying from 

 fifteen to twenty degrees farther north. The result of ten years' observations at 

 New- York, gives one hundred and sixty-five days, or about five months, as the 

 mean duration of winter ; but in the interior or northern district, many of the 

 counties have scarcely a month without frost. This, it will readily be perceived, 

 must exercise a great influence upon the number and distribution of its animals ; 

 for while it has the summer heats of Spain and Italy, the rigor of its winters 

 equals those of the northern portions of Europe. From this diversity of climate, 

 it results that we have in the State similar classes of animals with those found in 

 the northern parts of Europe, and at the same time other families existing chiefly 

 in its southern portions. The families Cervidce and Mustelidce may serve as 

 examples of the one, while the Vespertilionidce and Muridce will illustrate the 

 other. 



Varieties of surface are also well known to be favorable to the multiplication 

 of animal species, and in this respect, the State of New- York offers a great diver- 

 sity ; for although few of its mountains exceed the height of five thousand feet, 

 yet from the peculiarity of climate alluded to above, their summits have a tem- 

 perature much lower than mountains of even higher altitude in corresponding 

 parallels in Europe. The surface of New- York is considerably elevated, much 

 of it lying on the great Allegany table land. The diversity of surface is, how- 

 ever, so great, that for the purposes of more intelligible description, we may 

 consider it as divided into four principal zoological districts, each sufficiently dis- 

 tinct in itself, but of course so much blended at the lines of separation as not to 

 be contradistinguished. 



1. The Western District, includes that portion of the State which is bounded 

 on the west and north by Lakes Erie and Ontario, and on the south by the 

 boundary line separating it from the State of Pennsylvania ; and it extends east- 

 ward]}' until it is lost in the valley of the Mohawk on the north, and the moun- 

 tainous parts of the Hudson district. A large portion of this district is an elevated 

 region, furrowed by valleys running in a north and south direction, supposed 

 once to have been the outlets of a great inland ocean, but now the beds of rivers 

 which, pursuing opposite courses, discharge themselves on the one hand through 



