THE BLOOMINGTON MORAINIO SYSTEM. 263 



as the Wisconsin, even where deeply buried beneath it, There are numerous 

 instances of the occurrence of buried soils in the portion of Illinois occupied 

 by both the Iowan and the Wisconsin drift, and there is little doubt that 

 such soils occur below each drift, but seldom are two soils found in the 

 same exposure or well section. In a few cases the soils are referred with 

 confidence to the junction of the Wisconsin and Iowan, but in the majority 

 of cases they appear to be at the junction of the Iowan and Illinoian. An 

 inspection of the well records presented below will serve to make clear the 

 difficulties of interpretation. 



These well records indicate that buried soils differ greatly in elevation 

 within short distances in the portion of Illinois covered both by the Iowan 

 and by the Wisconsin drift. This difference in elevation may be due either 

 to the presence of two soil horizons or to an erosion of a buried drift sheet. 

 In the latter case the lower soil would have been formed in a valley, while 

 the higher would have been formed on the uplands. Were full records of 

 wells preserved, it might be possible to interpret such cases satisfactorily. 

 But usually the imperfections of the records are such that interpretations 

 can scarcely be made. It is therefore only in the portion of the Wisconsin 

 drift lying outside the Iowan that the lower limits of the Wisconsin are 

 clearly recognized. It is highly probable that the Peorian and the Sanga- 

 mon soil are each represented. A brief statement setting forth the varia- 

 tions in elevation of the buried soils in each of the counties occupied by 

 the Bloomington morainic system will serve to make more clear the 

 methods of interpretation as well as the difficulties of correlation in portions 

 of the district. 



In Kane County buried soils appear beneath a plain southeast of Bur- 

 lington at a depth of only 40 or 50 feet and at an elevation of about 850 

 feet above tide. The soil is here referred with some confidence to the 

 Peorian interglacial stage at the base of the Wisconsin drift. On the 

 elevated moraine southeast from this plain a soil is found at a depth of 

 180 to 200 feet and at an elevation of only 750 feet. It has been found in 

 several wells in the west part of T. 40, R. 7 E. This lower elevation is 

 probably due to its being a lower soil horizon, presumably the Sangamon 

 soil, at the junction of the Iowan and Illinoian sheets, though the instances 

 reported may chance to be in every case in the line of valleys cut in the 

 Iowan. The wide distribution, however, favors the interpretation that there 



