g TRANSACTIONS OF WAGNER 



THE LIFE FEATURES OF THE COASTAL PLAIN AND THE PIEDMONT 



animal life of the higher areas is a southward occurrence of the so-called Cana- 

 dian fauna of the more northern regions. The peculiar interest which attaches 

 itself to the physiographic boundary between the Piedmont and the Coastal 

 Plain in southeastern Pennsylvania is that it marks, in a more or less definite 

 way, a line of demarcation between the AUeghanian type of life and a decidedly 

 southern or austral type of life, a group of species which has received the name 

 of Carolinian fauna. The ''upland terrace" or ''fall-line" is thus approxi- 

 mately the boundary between a northern and a southern Kfe element. 



In the neighborhood of Philadelphia this difference between the northern 

 and southern life features is quite apparent. The Coastal Plain region to the 

 south and east is characterized by a decidedly CaroHnian type of fauna, while 

 the upland country to the north and west of the city is occupied mainly, as 

 before mentioned, by AUeghanian or transition-zone species. The distribution 

 of certain birds during the breeding season is a good index of this difference in 

 the two areas. The Worm-eating Warbler {Helmitheros vermivorus), a typical 

 CaroHnian species, is much more abundant in the woodlands of the southern 

 section of the Philadelphia district than it is in the northern portion, occurring 

 only sparingly in the upland country, and there confined to the timber along 

 the bottom lands of the streams that flow down among the hills. This species 

 may be said to reach the northward range of its distribution on the Atlantic 

 slope along the lower Delaware Valley, and is mainly confined to the western 

 side of the river, being of rare occurrence in southern New Jersey. It is like- 

 wise found during the breeding season in the lower valleys of the Hudson and 

 the Connecticut rivers, but not in the intervening higher land, a fact indicating 

 that certain physical conditions are present in these two river bottoms similar 

 to those prevailing in the lower Delaware and southward. Like features of 

 distribution are also true of two other species of warbler — the Blue-winged 

 Yellow Warbler (Vermivora pinus) and the Kentucky Warbler (Oporornis 

 formosus), though these birds have penetrated more generally into the wood- 

 lands for some distance beyond the Piedmont border. The Carolina Wren 

 {Thryothorus ludovicianus) , the Carolina Chickadee (Penthestes carolinensis) , 

 and the Tufted Titmouse {Baeolophus hicolor) are other species much more 

 abundant in the Coastal Plain region than in the hill country to the northeast 

 of the city. It must be borne in mind that this border line from the Susque- 

 hanna southward largely loses its significance as a faunal boundary from the 

 fact that an increasing southern latitude exerts more and more of an influence. 



