PAPERS ON GEOGRAPHY AND GEOLOGY 347 



PLEISTOCENE DEPOSITS IN LAWRENCE 

 COUNTY * 



Flemin W. Cox, University of Illinois 

 location 



Lawrence County is one of the border comities between 

 Illinois and Indiana, in the southeastern part of the state. 

 Since at this place the Wabash river furnishes the boun- 

 dary line between the two states, it forms the eastern 

 boundary of the county. The largest tributary entering 

 the Wabash from the west is the Embarrass river and it 

 flows through Lawrence county to its junction with the 

 Wabash in the southeastern part of the county. The 

 southern border of the Illinois Drift Sheet is about thirty 

 miles south, while the moraines marking the southern 

 edge of the Early Wisconsin Drift Sheet are about forty 

 miles north of the county. This portion between the 

 edges of the two drift sheets is significant because the 

 mantle rock which covers the county was derived chiefly 

 from the Illinois and Wisconsin Ice sheets. (See Map.) 



ELEVATION 



The average elevation of Lawrence County is approxi- 

 mately 450 feet above sea level. The range of elevation 

 is not great, about 250 feet. There are, nevertheless, two 

 distinct physiographic divisions, the upland and the low- 

 land. About one-third of the county is occupied by the 

 lowland of the Wabash and Embarrass rivers, while the 

 remaining two-thirds are upland. The mantle rock 

 which covers the county are Pleistocene deposits of the 

 Illinois and Wisconsin Ice sheets, and because of the 

 number of oil wells that have been drilled in the county 

 it has been possible to learn something of the character 

 and depth of these deposits. 



Since this paper deals with differences between the up- 

 land and the lowland it is necessary to point out their 

 respective locations. 



* This paper should be read with a map of the area before one. 

 The- best map of Lawrence County is the topographic map. which may be 

 secured from the State Geological Survey at Urbana, Illinois for from ten 

 to fifteen cents. 



