DRIFT DEPOSITS OF ILLINOIS. 11 



dred feet." and lie says, "it is largely composed of coarse gravel 

 and fine white sand. The gravel beds contain numerous bould- 

 ers, some of foreign material, and some derived from the lime- 

 stones of the adjacent region." 



In his report on Lee county, the same author gives the fol- 

 lowing section of a well in the town of Palmyra: 



Feet. 



Black mcmkl and subsoil 6 



Finely- comminuted buff yellow clay 12 



Blue compact laminated clay 10 



Black muck full of sticks, etc " 



Total 33 



The same author says further: 'Over the southern portion 

 of the county, the drift clays are probably thicker than in the 

 vicinity of Rock river. Where thickest, the blue clay is much 

 the heaviest de-posit, and is often underlaid by the black mud 

 of the above section, or a bed of gravel and dirt of variable 

 thickness." 



In his report on Whiteside county. Mr. Shaw says, in speak- 

 ing of the drift deposits: "At one locality, a well was sunk 

 twelve or fifteen feet through yellow unctuous clay, then blue 

 clay was struck, and in about fifty feet more a great quantity 

 ' of sticks and wood, apparently cedar and pine, was found. The 

 water in the well had, of course, a brackish taste. This woody 

 deposit was about at the base of the drift." 



In the survey of Kankakee and Iroquois counties, the late 

 Prof. Frank H. Bradley found conclusive evidence of the exist- 

 ence of an ancient channel which he supposed to have been a 

 western outlet for the waters of Lake Michigan, and I quote 

 the following description of it from his report, Geol. Survey of 

 111., Vol. IV, page 229, et seq: "The depth of this channel in 

 its northern part is unknown; but its western bank is seen on 

 the Kankakee, just above Momence, w r here the rock suddenly 

 breaks off, and probes forced to considerable depths found no 

 solid bottom. These facts were ascertained in 1867, by Col. 

 James Worrall, then of the Illinois River Survey, now of Har- 

 risburg. Pa., who also informs me that the same 'shoulder' of 

 rock is found on the Calumet, nearly due north from Momence. 

 In this part of its course, passing through very solid rocks, the 

 channel is rather narrow, rock having been found upon its east 

 side and south of the Kankakee, within seven miles of Mo- 



