124 iPROCEEDINGS MANCHESTER INSTITUTE 



Bpsom, Merrimack County (height 1590 feet), and Mr. W. D. 

 Davis has obtained specimens in Sutton, Merrimack County, 

 the exact locality being undetermined and the altitude in conse- 

 quence unknown. At Plymouth, in Grafton County, the north- 

 ern form is reported to be more abundant than the southern, 

 even in the valleys. In Crawford's Notch, in the White Moun- 

 tains, in the summer of 1900, George E. Burnham found the 

 northern form alone. 



The histor}^ and relationship of these two forms of red squir- 

 rel are of special interest as illustrating the influence of altitude 

 upon the geographic distribution of life in North America. 

 Naturalists were early led to attempt to divide the surface of 

 the land into faunal and floial regions or zones. Dr. C. Hart 

 Merriam has shown, in his paper on " The Geographic Distri- 

 bution of I^ife in North America," (Smithsonian Report for 

 1901), that no fewer than fifty-six authors have proposed such 

 divisions for this continent. The earlier writers defined their 

 regions chiefly by lines of latitude, but it was soon perceived 

 that some account must also be taken of elevation. 



In 1863, Prof. A. E. Verrill (Proceedings Essex Institute, 

 III, 138), basing his conclusions upon observation of the birds 

 in the breeding season, asserted that " The Adirondack region 

 of New York, the northern parts of Vermont and New Hamp- 

 shire, including most of the higher parts of the Green Mountains 

 and all of the White Mountains, and even the summit of the 

 higher Alleghanies, will be included in the Canadian fauna." 

 This was equivalent to declaring that the Canadian or Boreal 

 zone extends, by a chain of mountain tops or islands of cold, as 

 far south as North Carolina. 



Ten years later, Samuel H. Scudder, in his paper on "The 

 Distribution of Insects in New Hampshire " (Geology of New 

 Hampshire, i, 333) , observed that ' 'The northernmost Alleghani- 

 an and southernmost Canadian species graduall}^ decrease in 

 numbers away from their metropolis, and become confined to in- 

 creasingly lower or higher altitudes * * according as they are 

 Alleghanian or Canadian forms." 



Dr. Merriam, in the paper already cited, sa5\s of the Boreal 



