4 SOILS OF THE EASTERN UNITED STATES. 



the sloping or rolling land to 10 or 12 inches over the more level 

 areas, or where surface soil has accumulated through the washing of 

 higher lying areas. The subsoil in the majority of areas where the 

 type has been encountered is a stiff, heavy red clay extending to a 

 depth of 3 feet or more. In some areas, hoAvever, the immediate 

 subsoil is yellowish or reddish yellow in color, and the deep, char- 

 acteristic red color is not encountered until a depth of 2 or 3 feet 

 is reached. In all cases the subsoil rests upon the underlying rock. 

 This is usually a fine-grained, massive, gray or blue limestone, 

 although in some areas marbleized limestone gives rise to this 

 soil. In the bluegrass region of Kentucky thin beds of shale which 

 are associated with the limestone contribute to the material which 

 forms this type. 



In all the northern areas of its occurrence the surface soil of the 

 Hagerstown clay is prevalently granular and in good mechanical 

 condition. In many of the more southern areas where erosion has 

 been excessive the surface soil is a stiff, hard clay, very difficult to 

 till, and for that reason the type is not generally occupied for agri- 

 cultural purposes in these latter areas. 



The Hagerstown clay is easily distinguished from the Hagerstown 

 loam, with which it is associated, by the stiff, plastic character of 

 both the surface soil and the immediate subsoil in the majority of 

 areas where it occurs. These two types and the associated members 

 of the Hagerstown series are easily distinguished from the other soils 

 in the region in which they occur through the fact of their derivation 

 from limestone rock in a valley position. The soils of the Hagers- 

 town series are distinguished from those of the Clarksville series 

 through the fact that the soils are brown or reddish brown and sub- 

 soils usually a deep red or reddish brown, while the surface soil of 

 the Clarksville types is usually gray and the subsoil yellow or red- 

 dish yellow. 



SURFACE FEATURES AND DRAINAGE. 



The Hagerstown clay, while occurring in valley or basin positions, 

 is neither level nor of low elevation. It is found principally upon 

 the rolling surface of valley floors, upon low ridges, and even upon 

 the isolated rounded hills or on interrupted ranges within the broader 

 limestone valleys. In the bluegrass region of north-central Kentucky 

 the Hagerstown clay occupies rolling to steeply sloping upland posi- 

 tions, where numerous small hills are separated by deeply cut stream 

 channels. As a result of this topographic position the natural sur- 

 face drainage of the soil is usually complete. In fact, upon all of the 

 steeper slopes, particularly in the more southern areas of its occur- 

 rence, the drainage is so complete that erosion constitutes a serious 

 problem in the cultivation of the type. 



