PHYSICAL GEOGRAPHY OF THE REGION. 75 



the Papilionidae, then it will be in place to discuss further the proper 

 serial or other arrangement of butterflies. Until they can , the numerous 

 characters by which the Papilionidae, and the Papilionidae alone, are 

 related to the Hesperidae must be regarded, with the series shown above, 

 to settle the matter beyond reasonable dispute. The facts, as known at 

 present, admit of l)ut one interpretation. 



III. 



THE PHYSICAL FEATURES AND FAUNISTIC DIVISIONS 

 OF NEW ENGLAND. 



THE PHYSICAL GEOGRAPHY OF NEW ENGLAND. 

 BY W. M. DAVIS. 



"Yours for iustauce, you know physics, something of geology, 



Mathematics are your pastime; souls shall rise in their degree; 



Butterflies may dread extinction, — you'll not die, it cannot be ! 



Browning.—^ Toccata of GaluppVs. 



New England is a rugged country of mountainous structure, worn down 

 to a moderate relief in its old age, depressed so as to submerge part of 

 its margin beneath the sea, and unevenly veneered over with a broken 

 sheet of drift, which covers many of its smaller hills and buries nearly all 

 the valley-bottoms out of sight. It is built in greatest part of crystalline 

 or of old and much disturbed bedded rocks, that have undoubtedly at some 

 former time given it a much stronger relief than it possesses at present ; 

 but it is now so long since its rocks were crowded into upheaval and ex- 

 trusion that little more than the roots of its old mountains remain. Indeed, 

 its rocks are so old, and even the last period of its overturning so remote, 

 that it has probably been at some time in the past denuded to a surface of 

 gentle undulation ; and it is in this surface that the present valleys ha^•e 

 been cut after a later time of general elevation. But even this change is 

 ancient, for little of the old surface can now be seen. It may be re- 

 constructed from such remnants as the plateau-like uplands of central or 

 western Massachusetts, where the relatively deep and narrow ^•alleys of 

 Deerfield and Miller's rivers, that enter the Connecticut from the west 

 and east near Greenfield, show that a good volume of high-level country 

 still remains there to be consumed ; it may be faintly perceived at a greater 

 altitude in the White Mountains, where the broad surfaces between the 

 dark glens, that are now eating their way back into the mountain masses, 

 manifest little topographic sympathy with the complicated structure of the 

 upturned rocks : but in the greater part of New England, the larger streams 



