10 
SOIL SURVEY OF BUFFALO COUNTY. 
corresponds to the family which is made up of different individ¬ 
uals having the same parentage. The Miami series, for example, 
includes light colored, glacial material where the soils have been 
derived largely from the underlying limestone, and the soils in 
the series range in textuie from a clay loam to sand and gravel. 
The Plainfield series includes light colored soils in regions where 
no limestone is present, where the parent rock was largely sand¬ 
stone, and where the material occurs as outwash plains or stream 
terraces. The soils in this series also have a wide range in tex¬ 
ture. The name used for a soil series usually indicates the local¬ 
ity where that particular series was first recognized and mapped 
by the Soil Survey. 
By uniting the name of the soil class which refers to texture, 
with the name of the soil series which refers chiefly to origin, we 
get the soil type which is the basis or unit of classifying and map¬ 
ping soils. A soil type thus, is a soil which is uniform through¬ 
out 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 work should be conducted, every farmer 
should be familiar with the soil types on his farm, and their lead¬ 
ing characteristics. 
