FAUNAI. DISTRICTS OF NEW ENGLAND. 93 



vicinity of the river. J5ut to the west of the region thus enclosed the Ca- 

 nadian fauna inchides the Adirondacks region, west of Lake Champlain. 

 The southern nuirsfin of this broad interfaunal or bifaunal belt starts 

 from some point in Massachusetts Bay not far southeast of Boston, and 

 passes westerly in such a way as to include in the true Alleghanian fauna 

 the entire belt of low lands along the southern coast of New England ; 

 but more than that it includes two considerable prominences thrust up the 

 Connecticut and Hudson Rivers, as far north as Winsor and Poughkecp- 

 sie respectively. While just to the northwest of the latter the extended 

 Canadian fauna embraces the Catskill region. 



It will thus be seen that this great interfaunal or bifaunal belt sweeps 

 across the whole of Xew England from west to east, and indeed embraces 

 within its limits tlie greater part of its territory. As it passes from the 

 west toward the sea an upper member follows north-eastward the valley 

 of the St. Lawrence, but fails to reach the ocean ; Avhile the main belt, 

 separated from the former by the great Adirondacks region, though 

 narrowly connected with it along the valley of Lake Champlain, sweeps 

 over the mass of New England : so that the study of the New Eng- 

 land fauna becomes one of especial interest. If we study the relations 

 of this interfaunal belt to the physical features of New England and the 

 neighboring regions, we shall see that it is limited upon the north by a 

 line which would run not far from a contour curve indicating; a heisfht of 

 country of about eight hundred to one thousand feet ; but that it is 

 deflected to the southward by the great mountain elevations of the AYhite 

 Mountain area and the Green Mountain chain. In Maine it plainly 

 skirts the line which in general separates the lower undulating country 

 from the more broken, hilly regions of the north and it bears a similar 

 relation to the southern edge of the Adirondack district ; while its south- 

 ern margin, as far as New England is concerned, is marked by the belt 

 of lowlands which border the southern shore of the district, and is 

 deflected northward only along the sea margin at its eastern extremity 

 and up the valleys of southward flowing rivers. 



In illustration of the diflxjrent divisions referred to in the foregoing, we 

 may point out that the upper margin of this belt marks in a general way 

 the southern limits of such species of the Canadian fauna as Oeneis jutta, 

 Polygonia gracilis and satyrus, Eurymus interior, Pamphila mandan and 

 Erynnis manitoba ; Avhile Polygonia faunus, Aglais milberti, and Cincli- 

 dia harrisii extend further south so as to reach the true separating line of 

 the Canadian and Alleghanian fiiunas ; Cercyonis nephele, Basilarchia 

 arthemis, Eugonia j-album, Cyaniris pseudargiolus lucia, Pieris oleracea 

 and Amblyscirtes samoset extend even further than this, often to the re- 

 stricted limits of the Alleghanian fauna. Basilarchia proserpina (asty- 

 anax-ursula) and the hybrid transitional forms between Cercyonis nephele 

 and C. alope are principally confined to this belt. 



