THE SHELBYVILLE MORAINE. 205 



gravel is reached. The waterworks wells at Maroa have a depth of about 

 1 00 feet and terminate in gravel. 



At Clinton the drift is found to have the remarkable thickness of 352 

 feet, making the altitude of the rock surface there but 380 feet above 

 tide. In the record published by Worthen 1 twenty-seven changes in drift 

 structure are reported. The lower 140 feet of the drift is entirely sand and 

 gravel, while in the remaining 212 feet there are thin beds of sand and 

 gravel whose combined thickness amounts to but 47 feet, the bulk of the 

 deposit being of clayey constitution. Another boring about one-half mile 

 north of the one recorded is reported to have penetrated only 270 feet of 

 drift. In the vicinity of Hallsville, 6 miles west of Clinton, several gas 

 wells have been obtained in beds of gravel below blue till at depths ranging 

 from 96 feet to about 140 feet. Some of these wells furnished a sufficient 

 amount of gas to supply fuel for one or more stoves, but at last accounts 

 (1897) the supply was decreasing. 



The section 1 of one of these gas wells on James Barnett's farm shows 

 an interesting series of drift sheets separated by buried soils, as follows: 



Section of a gas tirell in drift near Clinton, Illinois. 



IVet. 



1. Soil and yellow clay... 15 



2. Blue clay 30 



3. Black soil, with wood 3 



4. Drab clay 8 



5. Black mold and driftwood 8 



6. Drab-colored clay 20 



7. Driftwood (log?) ..- 2 



8. Drab-colored clay 21 



9. Hardpan 12 



10. Drab-colored clay J 



11. Greenish clay 10 



12. Sand, etc 5 



Total 137 



Iii this section it is probable that only 1 and 2 are to be included in 

 the Shelbyville drift. Number 3 appears to be the Peorian soil which caps 

 the loess in the region outside the moraine, while 4 probabl}' represents the 

 loess and 5 the Sangamon soil between the loess and Illinoian drift. 



In the vicinity of Atlanta the drift has a known thickness of over 200 

 feet. Records of several wells were obtained which range from 125 to 210 



1 Geology of Illinois, Vol. VIII, p. 34. 

 'Published in the Geology of Illinois, 



Vol. VIII, pp. 58,59; also p. 13. 



