28 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 304 



FREDERICK SOUTH SECTION 



SEi NEi NEi sec. 18, T. 1 N. , R. 1 E. , Schuyler County, Illinois. 



in borrow pit, 1959. 

 Measured by John C. Frye, A. Byron Leonard, and H. B. Willman. 



Pleistocene Series Thickness 



Wisconsinan Stage (feet) 



Woodfordian Substage 

 Peoria loess 



12. Loess, tan to yellow-tan, massive, strongly calcareous 

 below a 4-foot surface soil (P-599 calcareous loess; 

 P-600 B-horizon of surface soil). Yielded fossil snails 

 (locality 29). 10.0 



11. Loess (weakly developed soil profile), medium tan-brown 

 with carbonaceous flecks and small spots of secondary 

 calcium carbonate, matrix weakly calcareous, non- 

 fossiliferous (P-598). 1.0 



10. Loess, gray-tan, massive, coarse, strongly calcareous 



(P-596 2 feet above base; P-597 9 feet above base). 15.0 

 Altonian Substage 

 Roxana silt 



9. Silt, coarse, pink with transition to tan in upper 2 feet, 

 weakly calcareous becoming strongly so in transition 

 zone at top, fossilif erous (P-594 middle; P-595 top). 7.5 

 8. Silt, coarse, and very fine sand, sandier in base, tan in 

 base becoming light tan-brown in top, massive, weakly 

 calcareous, sparse snail fauna (P-592 lower; P-593 upper). 8.0 

 7. Sand, fine to very fine, grading upward to silt, medium-tan 

 in base grading upward to light tan-brown, weakly 

 calcareous; sparse snail fauna (P-590 base; P-591 upper). 2.5 

 6. Silt, coarse, and very fine sand, pink, massive, compact, 



calcareous (P-589); contains fossil snails (locality 29). 3.5 

 5. Sand, fine, and coarse silt, medium gray-tan, calcareous, 

 massive, gradational top and bottom, nonfossiliferous 

 (P-588). ' 4.0 



4. Colluvium of silt with some sand, scattered coarse sand 

 grains and pebbles, tan to tan-brown, noncalcareous 

 (P-587). 2.0 



Pre-Wisconsinan Stages 



3. Soil, with 3-foot profile, red-brown B-horizon (P-586), 

 developed in silty sand, tan, noncalcareous, grading 

 downward through tan, noncalcareous sand and silty 

 sand (P-584 lower; P-585 upper), to 2 feet of calcareous 

 tan sand in base (P-583). 15.0 



2. Covered in lower part; coarse colluvium composed of sand, 

 silt, blocks of tan sandstone, metamorphic and igneous 

 rock pebbles; strongly calcareous and cemented in 

 discontinuous zones. 5.0 



1. Till, gray, calcareous, sandy and pebbly, abundant nodules 

 of CaC03 in lower 3 feet (P-581), strongly oxidized in 

 upper one foot (P-582); rests on Pennsylvanian sandstone, 4.0 



Total Pleistocene 77.5 



