330 THE ILLINOIS GLACIAL LOBE. 



exception of some short ridges of sand. There are also the following areas 

 within this plain where sand is not present: (1) A small area in eastern 

 Pulaski Comity, li miles north of Bruce's Lake; (2) an area south of 

 Brace's Lake extending south to Little Mill Creek and west about 3 miles 

 from the count)' line; (3) between Mill Creek and Little Mill Creek; (4) a 

 small area about Star City. This ridge lias an altitude nearly as great as 

 that of the ridge south of it, but its relation to that ridge and to the border 

 of tlie sand area was not clearly worked out. 



Another narrow sand ridge was traced by Purdue from Monon Creek, 

 about 5 miles southwest of the village of Monon, nearly directly west for 

 about 20 miles to Percy Junction in Newton County. This ridge con- 

 stitutes the south border of the main saud area in Jasper County. West 

 and northwest from the western end of this ridge there are a few low sand 

 ridges, but these occupy only a small part of the surface and do not have 

 definite connection with each other nor with the long ridge just mentioned. 

 There is enough surface sand, however, to indicate that that region was 

 covered by a body of water. The Iroquois moraine, on the north side of 

 the Iroquois River, appears to have been partially submerged, but its 

 highest ] tarts probably rose above the water and shut in a bay on the 

 south, in which wave action was not sufficiently strong to form heavy sand 

 deposits. 



The south border of the main sand area follows the north slope of the 

 moraine westward into Iroquois County, Illinois, and there swings south- 

 ward with the Iroquois moraine to Coon Creek, in southwestern Sheldon 

 Township, forming apparently an outwash apron, as noted above. 



A belt of dunes leads westward from this sand area across Belmont 

 and Crescent townships. There is considerable surface sand from this belt 

 of dunes northward, but to the west and northwest only occasional low 

 sandy ridges and thin patches of sand are found. A sand ridge, as noted 

 on a previous page, passes westward from the southwest part of the main 

 sand area in central Iroquois County through Onarga and Ridgeville to the 

 east fork of Vermilion River, through which there was probably a tem- 

 porary westward outlet to the Vermilion Basin, and thence to the Illinois. 

 Possibly this sand ridge and the belt of dunes with which it connects at 

 the east are independent of the sand bordering the Iroquois moraine. 



