10 
INTRODUCTION 
ample, includes light colored, glacial material where the soils 
have been derived largely from the underlying limestone, and 
the soils in the series range in texture from a clay loam to 
sandy and gravelly loams. The name used for a soil series usually 
indicates the locality where that particular series was first recog¬ 
nized and mapped by the Soil Survey. By uniting the soil class 
with the soil series we get the soil type which is the basis 
or unit of classifying and mapping soils. A soil type thus, is 
a soil which is uniform throughout its entire extent in texture, 
color, topographic position, and other physical properties, and 
having a distinct agricultural unity, that is, being adapted to 
the same crops, and requiring the same treatment. It is also 
uniform in the source of material from which it is derived, and 
the mode of origin which, taken together, determine the chemical 
composition. Since the soil type is the unit in classifying and 
mapping soils, and the basis upon which experimental w T ork 
should be conducted, every farmer should be familiar with the 
soil types on his farm, and their leading characteristics. 
