218 THE ILLINOIS GLACIAL LOBE. 



exceed 150 feet in thickness. As there are several moraines crossing this 

 district the discussion of its features is taken up in connection with them on 

 later pages 



CERRO GORDO MORAINE. 

 DISTRIBUTION. 



The CeiTO Gordo moraine emerges from beneath the Champaign 

 moraine opposite the village of Mahomet, in Champaign County, and fol- 

 lows the east border of the Sangamon River Valley, at a distance of 1 to 3 

 miles from the stream, from Mahomet southward to Cerro Gordo, a village 

 10 miles east of Decatur. It there swings away from the river, and is dis- 

 tinctly traceable only to Laplace, 6 miles south of Cerro Gordo, there 

 being for a few miles no definite continuation. A distinct ridge, however, 

 appears near Humboldt, in northern Coles County, which is supposed to 

 be its continuation. This ridge is traceable in a general eastward course, 

 but with slight windings, through southeastern Douglas and central Edgar 

 counties. 



The interval between the Cerro Gordo and Shelbyville moraines varies 

 greatly in width. Near the city of Paris they are closely associated ; at 

 Humboldt they are separated by a space of 10 or 12 miles, and a similar 

 interval is found opposite Cerro Gordo. From Cerro Gordo northward 

 the ridges pursue divergent courses, so that opposite Mahomet they are 

 separated by a space of 25 or 30 miles. 



TOPOGRAPHIC EXPRESSION. 



The portion of the moraine between Mahomet and Laplace consists of 

 an irregular aggregation of drift swells and short ridges, occupying a belt 

 about 2 miles in average width. The knolls are so closely aggregated that 

 very little plane surface is found among- them. The usual height is 10 to 

 20 feet, but a few are 30 feet or more above bordering low ground. The 

 belt is sharply in contrast with the level tract to the east, and has on the 

 whole a stronger expression than the Shelbyville moraine. 



The portion leading eastward from Humboldt presents more variation 

 in topography than the portion just mentioned. In northern Coles and 

 southeastern Douglas counties, and for several miles in western Edgar 

 County, it consists of a smooth till ridge one-half mile to a mile in width, 

 with a relief of 20 to 30 feet. In places it is but 60 to 80 rods wide, and 



