POST-WOODFORDIAN MOLLUSKS 



Fig. 1 - Excerpt from Sibley, Illinois, 15 -minute quadrangle map, contour interval 10 feet, 

 showing the location of the Strawn NE bog, and the position of the two hand-auger 

 borings, localities 135-1 and 135-2. The high ground to the east of the bog lake 

 is the front of the Paxton Moraine. A canal provides drainage for the basin, but a 

 colony of beavers maintains a dam that regulates the level of the lake. 



1934 to recover fossilferous, highly organic marl for use as a substitute for agri- 

 cultural lime and fertilizer. These operations have been virtually suspended. 



The cuttings from the two auger holes provided the samples upon which 

 the measured section is based and from which the molluscan faunas were recovered 

 Auger hole 131-1, according to judgments based upon local topography, is near 

 the southern shore of the original basin; here glacial outwash and/or till was 

 encountered at a depth of 14 feet. Auger hole 135-2 was bored about 200 yards 

 north, on the opposite shoreline of the present lake; it is judged to be near the 



