GROUP OP HARVEY SOlLti. 
23 
terial frequently becomes somewhat lighter, both in color and 
texture. Throughout the subsoil thin streaks of ashy gray fre¬ 
quently appear, and it is probable that these mark the location 
of former cracks into which surface silty material has been 
washed. Upon drying large cracks are formed in the surface 
and these extend to a considerable depth into the subsoil. These 
are of course most noticeable in uncultivated fields. Occasion¬ 
ally water worn gravel and a few small stones are found upon 
the surface and mixed with the soil but these are always of very 
limited number. In some places in the deep subsoil there is 
found a substratum of medium to fine sand. This is seldom 
more than a few inches thick when the red clay is again en¬ 
countered. This condition is found chiefly east of Fremont. 
Topography and drainage. —The surface of the Superior clay 
loam is level or nearly so, and because of the heavy character 
of the subsoil the natural drainage is deficient. Many farmers 
have laid out open ditches or have laid out the fields in narrow 
lands so that the dead furrows would serve as surface drains. 
Some of the most progressive farmers have installed tile drains 
with very marked success and it is only a question of time un¬ 
til practically all of this type will be fully tile drained. 
Origin. —The material forming this soil is largely of lacus¬ 
trine origin, but since its first deposition by quiet waters it has 
been more or less influenced by the action of glacial ice. Typi¬ 
cally the Superior soils contain considerable carbonate of lime, 
and varying amounts are found in this type, especially in the 
subsoil. The surface is usually not acid, though in some cases 
a slight acidity has developed. 
Native Vegetation. —The original timber growth consisted of 
hickory, oak, elm, birch, some maple, and poplar. By far the 
greater part of the timber has been removed. 
Present agricultural development * —A considerable propor¬ 
tion of the Superior clay loam is being utilized for farming pur¬ 
poses. The best drained portions are devoted to cultivated 
crops, and the less well drained tracts are used for hay and pas¬ 
ture. When thoroughly drained this is an excellent soil, though 
some what difficult to handle because of its heavv texture. Tt 
«/ 
is devoted to general farm crops consisting of hay, small grains, 
corn and potatoes, and where drained good yields are secured. 
* For chemical composition and improvement of this soil see page 25. 
I 
