324 
the latter is found in the fact that at one time the outlet of Big Muddy 
River into the Mississippi was filled up, iorming a large lake called “Big 
Muddy Lake,” which was northeast of this region. Glacial striae, having 
a general north and south direction, are found just east of this region at 
Bush, while in another place in the Herrin quadrangle they run south 
30 degrees west. 
Glacial deposits have been modified or covered up in places by loess, 
which was blown up by the wind from some of the great outwash plains 
formed by the glaciers. According to Savage, this may be of two kinds, 
the deep loess, which has a depth of 50 feet in places, and thin loess 
about 10 feet in thickness, the two often shading so imperceptibly into each 
other that they may be considered parts of the same deposit. The thick 
loess may have been deposited in the forested regions and the thin loess 
in the undrained lowlands. The true loess weathers with a more or less 
vertical face, gives a test for lime with acids, and contains the remains of 
land shells. A good example is found in the cut at Dug Hill, between 
Jonesboro and Ware, along what is known as the Dug Hill road. South 
of the Cache River in the Dongola quadrangle the loess is not typical but 
is non-calcareous, and can hardly be distinguished from the silt loams. 
SOIL TYPES 
A, Upland soils—In the upland area the variation in soils is not 
marked. Prevailing opinion holds that loess is present in almost all of the 
upland soils in degrees varying from light deposits in the eastern sections 
covered by this report, increasing to the west, to the true deep loess 
deposits on the bluffs from Dutch Creek, in the Jonesboro quadrangle, 
south to Thebes. The true loess contains a considerable percentage of 
lime, and we have found lime concretions imbedded in the banks of the 
streams. The loess soils, according to the “county advisers” in this 
region whom we have consulted, will grow good blue-grass, sweet clover, 
or red clover, and the presence of certain leguminous plants on top of 
some of these ridges shows that the soil contains considerable lime; hence 
is not at all acid, as many of the soils on run-down farms are apt to be. 
Two soil types, the yellow silt loam and the yellow-gray silt loam, 
together comprise over 80 per cent of the upland soils. They differ in the 
fact that the yellow-gray silt loam is an intermediate phase, approaching 
the gray silt loam on tight clay, being a mixture of the gray silt loams 
with the yellow silt. 
The three main soil types are shown in Plate LX XII: the mixed loam 
in the bottoms; the yellow silt loam on the sides of the hills and ravines ; 
and the yellow-gray silt loam on the tops of the ridges. Roughly speak- 
ing, the last two types are of about equal area, and are so represented. 
