1914.] NATURAL SCIENCES OF PHILADELPHIA. 443 



resulting from the decomposition and disintegration of the underlying 

 rocks. They are of a loamy texture containing relatively high pro- 

 portions of clay and silt and also holding in most instances a con- 

 siderable amount of available plant food. The Coastal Plain soils, 

 with some exceptions, represent detrital materials originally trans- 

 ported by water and floating ice from the front of the great continental 

 glacier. They consist almost exclusively of coarse gravels and sands 

 which contain extremely low amounts of clay or silt and are very 

 deficient in available plant foods. 



The differences in biota are also correlated with differences in 

 topography. The Piedmont Plateau is a region of considerable 

 relief and consequently of good drainage, so that marshy areas 

 constitute an insignificant feature of the region. The Coastal 

 Plain, with the exception of a portion along its western edge, is a 

 region of extremely low relief and poor drainage, so that marshes 

 form a very prominent feature of the region. 



Faunal Subdivisions. — The map accompanying Smith's report 

 on insects in the 1909 report of the New Jersey State Museum 

 subdivides the State into six faunal districts. This map was largely 

 based upon the results of Stone's studies on the distribution of 

 plants, although no acknowledgment of this fact is made in the text. 

 In the map accompanying Stone's report on plants already cited 

 the southern or Coastal Plain portion of the State is subdivided into 

 five districts. Stone does not consider the region north of the 

 fall-line in detail, but simply refers to it as the Northern District 

 without any attempt at further subdivision. In Smith's report 

 the same region is subdivided into three districts, i.e., the Appalachian, 

 the Highlands, and the Piedmont Plateau. All three of these sub- 

 divisions are represented in Pennsylvania. 



The subdivisions of the Coastal Plain recognized by Stone are 

 (a) the Middle District; (6) the Pine Barrens; (c) the Coastal Strip, 

 including the coast islands and a narrow strip of mainland adjoining 

 the salt marshes; {d) the Cape May Peninsula south of the Great 

 Cedar Swamp, and (e) the Maritime District, embracing the salt 

 marshes. 



In the case of the Orthoptera, these same subdivisions can be 

 readily, recognized, but to my mind thej^ are not all of equal f aunistic 

 value. As major or primarj^ faunal centres I would class the Appa- 

 lachian, Piedmont, Pine Barren, and Coastal districts, because each 

 of these is definitely characterized by a number of species which are 

 either entirely absent or relatively infrequent in the other districts. 



