THE MIAMI SERIES OF SOILS. 39 
The surface soil of this phase extends to an average depth of 10 
inches and consists of a light-brown friable silt loam. The color of 
the surface soil when dry is ashy gray. The subsoil is a yellow silt 
loam, which becomes heavier with increased depth, grading into a 
yellowish-brown silty clay loam at 20 to 24 inches. This material 
usually extends to a depth of 3 to 6 feet, where it is underlain by 
glacial till consisting of a mixture of sand, silt, clay, and gravel. 
There is a sharp line of demarcation between the silty material form- 
ing the surface soil and the immediate subsoil and between the sub- 
soil and the deeper glacial till. Stone and gravel are almost entirely 
lacking in the surface 2 or 3 feet, but are numerous in the deeper 
subsoil. A large part of this stony material consists of limestone. In 
some localities the underlying rock is encountered at a depth of 
2 feet or less. In general stony areas are of small extent within this 
phase. 
The topography of the Miami silt loam, deep phase, is gently 
roiling or undulating, and the surface slopes are generally smooth 
and gentle. Differences of elevation of 100 feet or more occur 
within the phase, and there are some distinctly hilly areas of rather 
small extent. The phase occupies the tops and sides of the low, 
rolling hills and the more gently undulating intervening plains. 
In a small area west of the Wisconsin Eiver, in Columbia County, 
this phase is distinctly hilly, with differences in elevation of 500 or 
600 feet. In general the surface drainage of the phase is good, 
although small depressed areas are in need of tile underdrainage. 
The deep phase of the Miami silt loam is the most productive part 
of the type. Practically all of it is under cultivation, all the general 
farm crops of the region being produced. Corn is the leading crop, 
and average yields of 40 bushels per acre are secured. Yields of 
as much as 70 bushels have been obtained. Oats occupy the largest 
acreage of any small-grain crop and give yields of 35 to 70 bushels, 
with an average of 40 bushels per acre. Barley also is grown, pro- 
ducing 20 to 45 bushels per acre. Some winter wheat is grown, giv- 
ing acreage yields of 15 to 30 bushels. The acreage of both wheat 
and barley is said to be decreasing. The thrashing of small grains 
on a farm located on this phase in southern Wisconsin is shown in 
Plate XII, figure 1. 
A large area of this phase is seeded to mixed timothy and clover, 
and yields of 1 to 2J tons of hay per acre are secured. In some 
localities difficulty has been experienced in securing a stand of 
clover, and timothy is being seeded alone. 
In Columbia County, Wis., several special crops are grown to ad- 
vantage on this phase. Green peas for canning produce 1,800 :o 
2,000 pounds per acre. Where allowed to mature, a yield of about 
15 bushels per acre of seed peas is secured. Beans also are grown, 
