1920.] 



NATURAL SCIENCES OF PHILADELPHIA 



85 



Grateful acknowledgement is made herewith to those who have 

 acted as guides in several of these places; to Dr. Everett G. Logue 

 and Mr. John P. Young, in central Pennsylvania; Messrs. Harold 

 W. Pretz and Edward S. Mattern, in eastern Pennsylvania; Pro- 

 fessor H. Justin Roddy, in southern Pennsylvania; and to Mr. 

 Harry W. Trudell, who has taken part in many of the expeditions, 

 and whose aid in pressing specimens of plants and in many other 

 respects has greatly facilitated the covering of the ground and the 

 obtaining of the data. 



Descriptions of Individual Localities 



A. Appalachian Mountain and Piedmont. (Alleghanian Zone.) 



Swamps north of Dover and south of Green Pond (Warren County) 



New Jersey. 



These two localities in the New Jersey Highlands were selected 

 from the large number available because they are easily accessible 

 and appear to furnish the maximum possible contrast in soil acidity 

 relations. Dover is on the main line of the Delaware, Lackawanna 

 and Western Railroad about 65 kilometers (40 miles) northwest of 

 New York City; Green Pond (one of several bodies of water in New 

 Jersey bearing that name) is two miles east of Bridgeville station, 

 on the "old line" of the same railroad, about 20 km. (12 miles) 

 southeast of Delaware Water Gap. In the swamps 3 km. (2 miles) 

 north of Dover, the country rock is granitic gneiss, and the glacial 

 drift is dominantly siliceous in character, the swamp waters being 

 as a result mediacid. In those south of Green Pond the country 



