372 POPULAR SCIENCE MONTHLY, 



orioles, the common dove, and tlie bob-white or quail do not 

 breed beyond its northern boundary. The brook trout does not 

 range south of this fauna, and the rattlesnake, the copperhead, 

 the puff adder, the green snake, the milk snake, and the water 

 snake are not found beyond its northern border. 



The Carolinian fauna is a distinctly southern type and char- 

 acterizes the upper austral zone, which includes that portion of 

 the coastal plain region that reaches from the foot of the Appa- 

 lachian highland to the " fall line " of the various Atlantic 

 streams. The northern limit of this fauna thus coincides with 

 the inland border of the coastal plain which we have already re- 

 ferred to and which may be looked upon as the true dividing line 

 hetiveen the North and South. The presence of such birds as the 

 cardinal, the yellow- breasted chat, the Carolina wren, the tufted 

 titmouse, the Acadian flycatcher, and the blue-winged, Kentucky, 

 and worm-eating warblers during the breeding season is a sure 

 sign of the Carolinian fauna. These species never go beyond its 

 northern limits. Moreover, such species as the brown thrasher, 

 the wood thrush, the house wren, the chewink, the dove, and the 

 field sparrow, which find their northern limit in the transition 

 zone, are far more abundant in the Carolinian region, and might 

 almost be regarded as representatives of its fauna. 



It becomes a matter of profound interest, not only to the orni- 

 thologist and the student of geographical distribution, but to 

 every one who has in his heart a love of woods and fields, to lo- 

 cate this natural boundary by such fine shadings as the nesting 

 place of a bird or the habitat of a forest tree. Let us take that 

 portion of the line that cuts off a small corner of southeastern 

 Pennsylvania. To the ordinary observer this special tract of 

 country presents no marked difference from the landscape a hun- 

 dred miles or more to the north or south of it. Its detail of fea- 

 tures is quite similar and seasonal changes follow much the same 

 course that they do in northern Virginia and southern New Eng- 

 land. To the northwest, beyond the low, irregular ridge of the 

 " upland terrace " that marks the gneiss and schist rocks of an 

 ancient shore line, the country breaks into the rolling hills and 

 dales of the interior uplands. To the southeast lies the flat low- 

 land of the Delaware plain, and beyond this the pine barrens and 

 marshes of the Atlantic coast plain of New Jersey. One who has 

 an eye for the woods, however, will note a certain change in the 

 trees from southern New England and the highlands of the Mid- 

 dle States. Groves of tall tulip trees, with their broad, smooth 

 leaves of shining green and large, creamy blossoms streaked with 

 orange that open toward the end of May, form a characteristic 

 feature of the woodland scenery. The sassafras and the persim- 

 mon are scattered more or less abundantly through the woods 



