SOILS OF THE EASTERN UNITED STATES AND THEIR USE-XXXI. 



THE PENN LOAM. 



GEOGRAPHICAL DISTRIBUTION". 



The Penn loam is an important general farming soil found in the 

 northern portion of the Piedmont Plateau. It occurs within the 

 limits of the Triassic basins within the Piedmont region from north- 

 central New Jersey through southeastern Pennsylvania and central 

 Maryland into the north-central part of Virginia. The Penn loam 

 has been encountered in seven different soil survey areas within 

 this region and has been mapped to the extent of 320.266 acres. It 

 is probable that within the entire region the type will be found to 

 cover more than 1,500 ; 000 acres. 



CHARACTERISTICS OF SOIL AND SUBSOIL. 



The surface soil of the Penn loam to an average depth of about 

 10 inches is a characteristic dark-red loam. The immediate subsoil 

 is most frequently a heavy red silty loam, grading downward into 

 a stiff red clay loam or clay. In many areas small fragments of 

 sandstone and shale are scattered through both the surface soil and 

 subsoil. The stiff clay subsoil usually rests upon the fine-grained 

 red sandstone or red shale from which the type has been formed 

 through the processes of weathering. 



The Penn loam is readily distinguished from the majority of 

 northern Piedmont soils by the deep Indian-red color of both the 

 surface soil and subsoil and from the other soils of the Piedmont 

 series through its obvious derivation from the Triassic sandstones 

 and shales. In the more southern areas of its occurrence this latter 

 characteristic facilitates separation from the red clay soils derived 

 from the crystalline rocks of the more southern Piedmont regions. 



SURFACE FEATURES AND DRAINAGE. 



The Penn loam occupies level, rolling, and sometimes hilly areas 

 within the northern Piedmont section. In general the area of this 

 type consist of broad, ridged plains or undulating valleys lying 



26458 12 3 



