16 DRIFT DEPOSITS OF ILLINOIS. 



The following average section of the drift deposits in the 

 western part of Sangamon and eastern portion of the adjacent 

 county of Menard, was furnished by Mr. Joseph Mitchell, a 

 professional well-digger, and probably fairly represents the gen- 

 eral character of the drift in Central Illinois w r here no unusual 

 amount of erosion had taken place. This section, however, 

 does not represent the full thickness of the drift, as the wells 

 were not continued quite down to the bed rock: 



Ft. In. 



No. 1. Soil and yellowish subsoil 5 to 10 



No. 2. Gray sandy clay (loess) 6 to 8 



No. 3. Mucky clay with wood, etc 2 6 



No. 4. Bluish boulder clay lo to 15 



No. 5. Soft blue clay 20 to 40 



Maximum , 75 6 



No. 3 of the foregoing section is not identical with either of 

 the old soils found at Blooming-ton, Decatur or Pana, but it 

 probably holds the same stratigraphical position as the "Forest 

 bed" of the Ohio reports, and the chocolate-colored clay be- 

 neath the loess at Quincy. 



At Virginia, in Cass county, however, one of the older soils 

 was found, as shown by^ the following record of the shaft at 

 that locality: 



Ft. In. 



Soil and brown clay 9 6 



Blue clay and hard-pan 57 6 



Black soil 3 



Hard-pan 46 



Total 116 



At the Palmer shaft, in Christian comity, the following record 

 was preserved of the drift beds passed through: 



Two boulder beds are reported in the foregoing section, the 

 first immediately below the yellow clay of the sub-soil, where 



