36 GEOLOGY AND MINERAL RESOURCES OF MISSISSIPPI. 
from which he collected Jackson fossils in Clarke and Wayne counties, Trotter's plantation, 
msec. 3, T. 10N.,R.7W. 
The Jackson has usually been described as being entirely made up of marls and clays, fotit 
recent investigations along the line of contact between the Jackson and Vicksburg have 
shown that there are from 50 to 75 feet of yellow, gray, or white siliceous unconsolidated 
sand at the top of the Jackson. Whether from a paleontologic standpoint this should be 
considered Jackson or Vicksburg is doubtful, since no fossils have been found in these sands. 
They are regularly stratified, showing that (hey were deposited very near the old shore, h. 
more or less current. Id places near the surface (lie sands are often cemented with iron 
oxide, causing some strata to resist erosion more than others. Thin bands of clay stone are 
also frequently found throughout the sands. They outcrop in various places in southern 
Madison County, where the Vicksburg limestone forms outliers on the upper Jackson. The 
exact stratigraphic position of the sands was first discovered in this vicinity. The following 
sections were obtained in Hinds and Madison counties, near the contact between the Jackson 
and overlying Vicksburg. 
Just west of the house of Handy Washington (colored), in sec. 9, T. 7 Nv, K. 1 E., the 
Vicksburg, which overlies (he upper Jackson, caps the top of the hill. At the base of the 
limestone are 2 feet of dark nonfossiliferous clay. "Below this are S to 10 feet of fine, sharp- 
grained, white siliceous -and, with irregular horizontal hands of iron-stained sand containing 
small particles of mica and grains ol glauconite. In appearance this is similar to some of 
the sand in the Grand Gulf, but in two different places the stratified sand lies unmistakably 
underneath (he Vicksburg limestone. Below the sand and extending to the bottom of the 
hill is a bed of stratified clay of a general gray color, with a large number of iron-colored 
clayey bands and occasional layers of dark-blue clay. The whole is quite siliceous and 
contains much mica. 
A good section of the upper Jackson is obtained along the road on the steep hill on the 
south side of a branch in sec. 10, T. 7 X., R. 1 E. 
Section of upper Jackson formation in sec. 16, T. 7 N., R. 1 E. 
<;. Columbia and Lafayette at top of hill. Feet. 
.">. Alternating beds of Vicksburg limestone and marl 30 
1. Calcareous gray clay 3 
3. Gray. Sandy, micaceous, stratified clay 25 
2. Reddish stratified sand containing bands of light-colored clay 15 
1. White, fine-grained sand 10 
Still farther north the white stratified sand often occurs in large deposits sufficiently pure 
for commercial purposes. 
In a deep gully on the east-west road in the NW. \ sec. 2, T. 7 N., R. 1 E., the following 
section of the Jackson sands occurs: 
Section of Jackson sands in sec. 2, T. 7 N., R. 1 E. 
Feet. 
:;. Columbia foam 3 
2. Lafayette 2 
1. Very fine-grained stratified sands containing mica, but no fossils or lime. The sand varies from 
cream white to pink in color and weathers into fantastic shapes 10 
Along Pearl River, between Jackson and Byram, the material at the top of the Jackson is 
decidedly sandy. 
In a deep branch flowing westward in the southern part of sec. 15, T. 4 N., K. 1 E., the fol- 
lowing relation exists between the Jackson and overlying Vicksburg limestone: 
Section of Jackson and Vicksburg formations in sec. I~>. T. \ .V., R. I /<.'. 
Feet 
4. Alternating beds of limestone and marl 20 
3. Chocolate-colored fossiliferous clay, containing crystallized gypsum and alum 15 
2. Pure lignite \ 
1. Green and chocolate-colored sands, cross-bedded, with occasional bands of clay, nonfossiliferous. 20 
