92 PROCEEDINGS OF THE ACADEMY OF [March, 



B. Coastal Plain. (Carolinian Zone.) 

 Pine Barrens and Marginal Areas of New Jersey. 



The correlation between soils and plants in southern New Jersey 

 will be discussed by the writer elsewhere. The following is a 

 summary of the conclusions there reached. 



As every botanist interested in plant distribution has undoubtedly 

 become acquainted with Stone's "Plants of Southern New Jersey, " 

 no description of the plants of this region need be given here. As to 

 soils, although pure quartz sand should react neutral toward indi- 

 cators, that of the Pine-barren area seems to be always more or less 

 acid, no doubt owing to the accumulation of invisible humus matter 

 between the grains; and where the humus is prominent, the reaction 

 is usually mediacid, so that the Pine-barren area can be regarded 

 as essentially a vast expanse of highly acid soils. On digging down 

 through the surface layers of these soils, the acidity gradually 

 decreases, and at a depth of three or four decimeters may be minima- 

 cid. Road-cuts and stream valleys through the region readily 

 reach the levels of lower acidity, and on their banks grow plants 

 which do best under somewhat less acid conditions, AspJenium platy- 

 neuron being a typical example. 



The upper part of the Middle District or Marl area differs from 

 the Pine-barren area in that mediacid soils are comparatively rare, 

 the sands containing greater amounts of compounds of calcium 

 and other elements which tend to neutralize more or less such acids 

 as develop. The strata of Cretaceous age which outcrop are well 

 known to contain considerable calcium carbonate derived from 

 fossil shells, and the soil has in fact been found to reach neutral or 

 even minimalkaline reaction in certain places, as for instance, the 

 Lindenwold bog. In the Cohansey and Cape May areas the acidity 

 also averages low, the source of the lime appearing to be sediments 

 deposited in Quaternary times by the Delaware River, which 

 drains vast areas of limestone rocks in its upper reaches, and the 

 water of which is today slightly alkaline. In the Coastal area 

 the sandy soils are mediacid as in the Pine-barrens, but contain 

 considerable sodium chloride, calcium sulfate, etc., so that plants 

 which require high content of salts, but are indifferent to acidity 

 as such, together with those which require acidity but are tolerant 

 of salts, are characteristic of this area. 



The distribution of plants is evidently controlled to a marked 

 degree by these features of the soils. As Stone remarks "The 

 Pines seem to be the chosen land of the Ericaceae, which abound 



