XYI. ]\IILL CEEEK QUARRIES, ILLIXOIS 



THE lower carboniferous formations of the Ohio Valley, more 

 especially in western Kentucky and southern Illinois, yield 

 chert concretions of different material from those of south- 

 ern Indiana, which wore extensively utilized by the aborigines. The 

 only important ({uarries of this class thus far discovered and ade- 

 quately studied are those located in Union and AU^xander Counties, 

 in southern Illinois. That there are others scattered through the 

 hills and valleys of the general region is well attested by surface 

 indications of prehistoric diggings and the occurrence of chipped 



Fig. 03. Map of the Mill Creek quarry site. 



implements made of materials other than those derived from the 

 well-known sources. 



In the vicinity of Mill Creek village, a station on the Illinois 



Central Railway, Union County, and extending over 

 Exploration of the -^^^^ Alexander County on the .south (fig. 03), chert 



concretions weathered out from the limestone for- 

 mations were quarried on a large scale. These concretions were 

 especially well suited, on account of their size and shape, for the 

 manufacture of the large chipped blades used as agricultural imple- 

 ments by the aborigines. The site was first visited and examined 



187 



