DISTINGUISHING OF SOILS SIMPLIFIED 23 



mapped hundreds of thousands of acres of soil. Each soil 

 map is accompanied by a report describing in detail the nat- 

 ure and agricultural value of the soils surveyed. These 

 surveys are usually made by counties and are based on the 

 theory that all soils are not equally suited to the production of 

 the same crops. 



One Loam May Differ Widely from Another.— Though a class 

 of soil consisting of about half sand and the remaining half silt 

 and clay, for example, is a loam wherever found, yet a loam in 

 Wisconsin may differ in ten distinct ways from a loam in Missis- 

 sippi, and have dissimilar crop adaptation. In order, therefore, 

 to distinguish clearly between these two particular loams, long 

 descriptions must necessarily be given each one, concerning man- 

 ner of formation, kind of material from which formed, natural 

 drainage, color, amount of organic matter, structiue, subsoil and 

 certain chemical properties. 



Distinguishing of SoUs Simplified. — In soil mapping it would 

 be very inconvenient, indeed, if it were not possible to designate the 

 different soils without describing each in its fullest detail, especially 

 since there are so many different kinds of soils in the United States 

 to be correlated. 



Soil descriptions concerning origin, etc., may be expressed in 

 single words; for example, ^^ Dunkirk," "Greenville," etc. These 

 names used in describing soils are derived from the name of some 

 town, village, coimty or natm:al feature existing in the section or 

 region where the soil is first identified or is best developed. 



Dunkirk, as it is used in describing soils, implies that such 

 soils are derived from sandstone, shale and hmestone material 

 carried as sediment into pre-existing glacial lakes; they have good 

 natural drainage; are gray to brown in color, and have a yel- 

 lowish or light brown subsoil. These soils are desirable for 

 general farming. 



Greenville is a descriptive name signifying that such soils are 

 of marine origin — ^built up by material washed from the Piedmont- 

 Appalachian region into the ocean which at one time encroached 

 upon the continent; they are red in color; have a dark red subsoil; 

 and are friable and well drained. They are well adapted to cotton, 

 corn, forage crops and oats. 



Wherever a loam is found to which will fit the description 

 implied in "Dunkirk," liiat soil is specified as "Dunkirk loam." 

 And wherever a loam is found to which the descriptive term 



