Plate XI, at p. 465. 
Harshberger, Survey N.-America. 
a. Wissahickon Creek 
Fairmount Park, Philadelphia (Piedmont Plateau Distriet), Deciduous Forest Formation. 
b. Hemlocks, Tsuga canadensis (L.) 
in pure formation above Stony Creek, near Shenandoah City, Penna. 
(Appalachian District). Coniferous Forest Formation (Tsuga Facies). 
