2 ROCHESTER ACADEMY OF SCIENCE. 



were dammed at the close of the glacial period by the retreating ice 

 sheet, and are now occupied by the central chain of lakes. The north- 

 ern belt is a level or slightly undulating plain widening toward the 

 east. Its lowest portion, lying along the southern shore of Lake 

 Ontario, and about Oneida, Cayuga and Seneca Lakes, is below 500 

 feet in elevation. The drainage of the northern and middle belts is 

 through the St. Lawrence system. 



FAUNAL AREAS. 



Western New York lies principally in the Transition life zone, as 

 mapped by Dr. Merriam (Bui. No. 10, Biological Survey, U. S. 

 Dept. of Agriculture, and in the Geographic Distribution of Life in 

 North America, Smithsonian Report, 1891). 



This zone stretches across the northern portion of the United 

 States and southern Canada, and is divided into the eastern, or humid, 

 and the western, or arid, regions. The humid division, which is the one 

 represented in western New York, is know r n as the Alleghanian faunal 

 area, and there corresponds very nearly with the middle and southern 

 belts defined above. This fauna includes the greater portion of our 

 characteristic birds. 



The Upper Austral life zone, which in general lies south of the 

 Transition zone, has its humid division east of the icoth meridian. 

 This is known as the Carolinian fauna, an extension of which stretches 

 along the northern shore of Lake Erie, passing into western New 

 York along the southern shore of Lake Ontario, widening toward the 

 east and south through the central lake region, thus corresponding in 

 western New York to the northern belt of low, undulating plains. 



The Boreal region, which includes the transcontinental coniferous 

 forest belt of Canada, passes southward along the mountain ranges of 

 the United States, and reaches western New York near the southern 

 jine, in the counties of Steuben, Allegany and Cattaraugus, where the 

 altitude rises above 2,000 feet. 



The southern division of the Boreal region here represented is 

 known as the Canadian zone. Thus the warmest life belt of our region 

 lies farthest to the north, the coldest to the south, the influence of 

 altitude, and the modifying effects of the Great Lakes, combining to 

 transpose the normal positions of the life zones. 



To the Carolinian fauna belongs the greater portion of our sum- 

 mer visitants, and a goodly number of the summer residents of the 

 northern belt of western New York mentioned above. Such repre- 



