WISCONSINAN MOLLUSCAN FAUNAS 



27 



Silt) indistinctly bedded to massive, compact, red-tan 

 to gray-tan, with a few streaks of sand; maximum 

 thickness in west side of quarry, pinching out to 

 the east (P-274). 



Pleistocene depo-sits rest on Mississippian limestone. 



Maximum total thickness 



Thickness 

 (feet) 



5.0 



79.0 



ickness 

 (feet) 



25.0 



15.0 



COTTONWOOD SCHOOL SECTION 



Center E. line, sec. 11, T. 18 N. , R. 11 W. , Cass County, Illinois 

 Measured along road cuts, 1958, 1959, by John C. Frye, 

 A. Byron Leonard, and H. B. Willman. 



Pleistocene Series Th 



Wisconsinan Stage 



Woodfordian Substage 

 Peoria loess 



9. Loess, coarse, gray-tan to pale yellow, massive to 

 indistinctly thin-bedded and laminated, sparsely 

 fossilif erous, calcareous (P-110). 



8. Loess, coarse to medium, massive, gray-tan, a fine- 

 textured zone gradational at top (P-109), indistinct 

 streaks of pale pink throughout, calcareous (P-107 

 and P-108); contains fossil snails (locality 32). 

 Altonian Substage 

 Roxana silt 



7. Loess, coarse, massive, dark pink in lower part (P-104) 

 grading upward (P-105) to pinkish gray in upper part 

 (P-106); noncalcareous to weakly calcareous, very 

 sparsely fossiliferous throughout. 15.0 



6. Loess, medium, massive, neutral gray, limonite tubules, 

 weakly calcareous; sharp contact at top (P-102, lower; 

 P-103 upper). 10.0 



5. Loess, medium, massive, pinkish-tan, gradational upward 

 with gray loess and sharp contact at base; limonite 

 tubules and small calcium carbonate concretions through- 

 out, weakly calcareous but nonfossilif erous (P-100, 

 lower; P-101 upper). 8.0 



4. Silt, massive, light gray to medium gray with some mottling 

 with tan, noncalcareous; small angular fragments of chert 

 and small pebbles sparsely throughout; colluvium (P-99). 5.0 

 Illinoian Stage 



3. Till, compact, pebbly and cobbly; in lower half gray, 



calcareous, tough (P-97); upper half in soil profile, 



leached, red-brown, sandy, clayey, friable (P-98). 8.0 



2. Silt, compact, blocky, calcareous, banded gray and tan, 



contains some sand and pebbles (P-96). 3.0 



1. Till, compact, massive, pebbly, calcareous, gray to gray- 

 brown (P-95); rests on Pennsylvanian shale and siltstone. 5.0 



Total Pleistocene 



94.0 



