A local deposit of Chester Sandstone. — Ovicides. 47 
A LOCAL DEPOSIT OF CHESTER SANDSTONE. 
By J. M. Nickles, Sparta, 111. 
Chester, Illinois, is the locality of the typical exposure of the 
Chester group. A section of the bluff from the court-house to 
the Mississippi river is as follows : 
No. 1. Soil and sandstone, not exposed 73 feet. 
2. Limestone, 1 " 
3. Green, blue and purple marl, 12 " 
4. Limestone, regularly bedded, 7 
5. Limestone, irregularly bedded, 42 
0. Green and purple fissile shale and marl with 
thin bands of limestone, .*>:; 
7. Limestone with occasional partings of green 
and blue shale, S2 
270 " 
Several hundred yards northwest of the court-house occurs a 
local deposit about twelve feet in thickness in the bluff, of soft 
yellowish homogeneous stratified sandstone, overlying conformably 
the lowest limestone of the preceding section. The deposit covers, 
perhaps, three acres. Its extent may be greater, but no evidence 
was found to warrant assigning it a larger area. The rock has 
been opened for about one hundred feet in longitudinal extent and 
is quarried for doorsills, window caps, and similar purposes, work- 
ing ver}^ easily. Northwest of the sandstone is a ravine intersect- 
ing the bluff, at whose bottom is a small stream flowing into the 
Mississippi river. The other side of the ravine shows no evidence 
of the sandstone deposit, though the sandstone may be there 
covered up by drift and soil. On the south side of the ravine the 
sandstone may be traced for a short distance up the ravine, and 
then disappears under the drift. 
Prof. A. H. Worthen, in the Geologj- of Illinois, vol. i, p. 
285, comments on this sandstone, instancing it as an example of 
the variability of the Chester beds. After giving a section of 
the bluff, similar to that above, but differing in the thickness as- 
signed to some of the beds, lie states that the bed of green and 
blue shales is quite variable in character, especially towards the 
base; that not more than a hundred yards above the point where 
lie made his section, there is a bed of sandstone, replacing the 
