30 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 304 



Thickness 

 (feet) 



3. Loessj gray-tan, massive, calcareous, nonfossiliferous, 



gradational contacts (P-575). 1.5 



2. Silt, contains pebbles in lower part becoming sparse 



upward (colluvium), pink (P-574). 4.0 



Pre-Wisconsinan Stages 



1. Sand and gravel with well developed soil B-horizon, red- 



brown, clayey, at top truncated by colluvial contact; 



grades downward into calcareous sand, gravel, and silt, 



well bedded to poorly bedded (outwash), partly covered 



in lower part to level of road. 50.0 



Total 99.5 



"THE ROCKS" SECTION, KENTUCKY 



One mile southeast of bridge across Ohio River at Shawneetown, Illinois. 

 Measured July 1959 by John C. Frye, A. Bryon Leonard, and H. B. Willman. 



Pleistocene Series Thickness 



Wisconsinan Stage (feet) 



Woodfordian Substage 

 Peoria loess 



5. Loess, gray, massive, calcareous below the surface soil; 

 fossil snails from lower two-thirds of this zone 



(locality 57A). (P-480 lower.) 20.0 



Farmdalian Substage (latest transitional) 



4. Loess, gray, massive, coarse, contains CaC03 nodules; 



fossil snails (locality 57B). (P-479). Radio- 

 carbon date on snail shells 22,200 450 (W-867). 5.0 

 Altonian Substage 

 Roxana silt 



3. Loess, dark gray to light brown, pink in basal part, 



massive, noncalcareous to weakly calcareous, non- 

 fossiliferous. This and underlying beds are trun- 

 cated at a low angle by erosional unconformity at top 

 so that bed 4 rests on bed 1 at side of cut (P-478, 

 top; P-477, middle; P-476, base.) 6.0 



Illinoian Stage 



2. Sangamon soil; red to red-brown clay and silt, scattered 



Mn-Fe pellets, clay skins, gradational at base. 



(P-475, upper. ) 4.0 



1. Silt, massive, mottled yellow, tan and red-brown in upper 

 part grading downward to yellow-tan, noncalcareous, 

 nonfossiliferous; rests on Pennsylvanian sandstone 

 (P-474, upper.) 6.0 



Total Pleistocene 41.0 



SAVANNA SECTION 



Adjacent to Highway 80, southwest cor. NW?- sec. 11, T. 24 N., R. 3 E. , 



Carroll County, Illinois (July 1959). 



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



