474 PROCEEDINGS OF THE ACADEMY OF [June, 



divide the land possesses a moderate amount of relief; here the 

 streams have cut ravines of from 50 to 100 feet in depth. Near the 

 Delaware, however, the surface is an almost level plain with the 

 streams meandering sluggishly through wide tidal mud-flats. In 

 their upper courses there is sufficient fall to enable the streams to 

 effect fairly adequate drainage, so that extensive inland bogs com- 

 parable to those at the heads of the Pine Barren streams, are excep- 

 tional. In their lower reaches the streams are so near tide level 

 that drainage is extremely imperfect and, as a result, the low flats 

 bordering the streams are kept in a state of perpetual saturation. 



The soils of the Middle District are much more varied than are 

 those of the other subdivisions of the Coastal Plain. The most 

 frequent is the Norfolk sand which occurs at practically all levels. 

 As a rule, it is thinner than in the Pine Barrens and the resultant 

 proximity to the water-table probably accounts for the somewhat 

 less xerophytic aspect of the vegetation which in West Jersey grows 

 on this type of soil. At higher elevations, where Norfolk sand is 

 naturally drier, it is not readily cultivable and is accordingly mostly 

 forested, the dominant tree growth consisting of pines {Pinus 

 virginiana and rigida), oaks {Quercus alba, stellata, prinus, marylandica 

 and ilicifolia) and hickories (Hichoria alba and glabra). At lower 

 levels, as in the immediate vicinity of the Delaware River, where the 

 surface of the sand approaches close to tide level, conditions obtain 

 similar to those of the Coastal Strip, The sand here is quite product- 

 ive, and consequently most of the country is cleared and used for 

 farming purposes. 



Locally there are extensive tracts of loamy soils developed in 

 West Jersey which in many respects closely ai)proach the Piedmont 

 soils. The more important of these are the CoUington sandy loam 

 and the Sassafras loam. The former is derived from the green sand 

 or glauconitic marls of the Cretaceous series. This material is 

 highly retentive of moisture and is also extremely rich in available 

 plant-foods. The CoUington sandy loam is largely confined to the 

 vicinity of the streams along which the greensand layers have been 

 exposed by erosion. Owing to its richness, nearly all areas of this 

 soil are under cultivation; the forests persisting only on the steeper 

 slopes along the streams. The vegetation is decidedly mesophytic 

 in aspect, the usual tree growth consisting of white, black and red 

 oaks, hickories, chestnut, beech, tulip-trees, red cedar, sweet gum, 

 red maple and dogwood. 



The Sassafras loam is typically represented in the vicinity of 



