1 78 GEOLOGICAL SURVEY OF NEW JERSEY. 



once be seen that climatic conditions alone are not sufficient to 

 account for all the facts of distribution and limitation which 

 may be observed, and that local physiographic and meteorologic 

 influences must be considered, such as altitude, minor surface 

 inequalities and configurations, presence and absence of moisture 

 in the atmosphere, presence of or proximity to water, &c. 

 Finally, if the investigations be carried yet further, it will be 

 appreciated that soil characteristics, both mechanical and chem- 

 ical, also play an important part in the matter. This source of 

 influence may be termed the geologic factor, for the reason that 

 the character of the soil in any locality is directly dependent 

 upon the character of the geologic formation from which it is 

 derived, and it is with this factor that this report is especially 

 concerned. 



It is unfortunate that by far the greater number of areal 

 investigations which have been undertaken have necessarily 

 been restricted by artificial boundaries, generally political, such 

 as state or county lines, instead of having been extended to 

 their natural limits, either physiographic or geologic, and many 

 interesting problems for this reason have been only indicated or 

 partially solved. The investigations upon which this report is 

 based fall within the same category, and there is no doubt that 

 if these could be carried out beyond the state lines, whatever 

 value they may have would be enhanced in proportion to the 

 distance or area covered. 



In the state of New Jersey, for example, two broad, contrast- 

 ing regions of forest conditions have long been recognized, viz., 



NOTE. In order that the meaning of certain terms may be clearly understood, the following defini 

 tions are appended : 



Distribution may be defined as geographic range. Thus, " Middlesex and Mercer counties, south- 

 ward to Cape May," would represent a geographic range or area of distribution. A species may have a 

 wide distribution and yet be rare, for the reason that it may only be able to exist under conditions which 

 obtain in but lew localities within the area of distribution. 



Locality or Station defines some particular place. Thus, " Middlesex county, near Perth Amboy," 

 would represent a locality or station. 



Habitat means character of surroundings. Thus, ''rocky hillsides," " salt marshes," " dry, sandy 

 soil," &c., would be habitats. 



A typical species of any region or area is one which is either confined to such region or area, or 

 which only extends beyond it in limited numbers or under specially favorable circumstances. 



A characteristic species oi any region or area is one which is so abundant as to be a prominent 

 feature over such region pr area, although not necessarily confined to it. 



