LIGHT COLORED UPLAND SOILS. 
17 
CHAPTER II. 
LIGHT COLORED UPLAND SOILS. 
Knox Silt Loam 
Description .—The surface soil of the Knox silt loam to an aver¬ 
age depth of 10 inches consists of a light-brown or grayish friable 
silt loam. When dry it has a smooth, floury feel. The amount of 
organic matter present in the soil is rather small, and this ac¬ 
counts, in part, for the light color. The subsoil consists of a yel¬ 
lowish-brown or buff-colored silt loam, which becomes heavier, 
more compact, and claylike with increased depth, until, at about 
18 to 24 inches, it is a silty clay loam. The soil mantle extends to 
an average depth of probably 8 to 12 feet. The underlying rock 
was not reached with the soil auger except in local spots on a 
narrow ridge, at the edge of a bluff, or at the head of a ravine. 
Both soil and subsoil are practically free from stone, gravel, or 
other coarse material, although occasional fragments of chert 
are to be seen on the surface or in the subsoil close to the lime¬ 
stone rock. On account of the heavy subsoil and the uniformly 
silty character of the soil, the type is commonly referred to by 
farmers throughout the county as a clay. 
The most important variation in this soil has been designated 
as the steep phase, on account of its steep slopes and rough, un¬ 
even topography. This phase is described in greater detail fol¬ 
lowing the description of the typical soil. 
Minor variations in the typical soil occur, chiefly on the nar¬ 
row ridges, where the surface soil has sometimes been removed 
and the heavy subsoil exposed. In such places the depth to the 
underlying rock is also less than over the more extensive areas 
of this type and in some instances it can be reached with a 3-foot 
auger. On some of the lower slopes the wash from adjoining 
higher land has accumulated to a small extent, and the surface 
soil in such places is somewhat deeper than the average. On some 
slopes the soil is somewhat darker in color and contains more 
