KANKAKEE AND IROQUOIS COUNTIES. 229 



I 



Dr. E. Andrews, of Chicago, as well as from the publications of Profs. Richard 

 Owen* and R. T. Brownf, and from reports of railroad surveys. 



1 have been unable to obtain any satisfactory information regarding the 

 character and levels of the country between South Bend and Lake Erie. It 

 seems highly probable that when that lake stood at the level indicated by the 

 highest terrace upon its ancient shores, not far from two hundred and fifty feet 

 above its present level (say eight hundred and fifteen feet above the ocean), it 

 should have had an outlet toward the west ; and this must have been either 

 the Kankakee or the Wabash. 



The sloughs which lie between the sand ridges of the old valley are filled 

 with soft black muck, which is just the material needed to make these sandy 

 portions exceedingly productive j when drained of the surplus water, they are 

 themselves unsurpassed as corn-land. In their present condition, they would 

 appear to be just the places for the culture of cranberries for the Chicago 

 market. 



Upon the bottom of Beaver lake, just east of the State line, since it has 

 been partially drained, skeletons of Mastodon and Bootherium have been found 

 by Dr. H. M. Keyzer, of Momence, and others ; and it is not improbable that 

 remains of these animals will also be found within the limits of Kankakee 

 county. 



Drift Formation. The drier portions of the county, out of the river valleys, 

 are mostly high, rolling prairie, with a few small groves, which shows but a 

 slight covering of soil and thin clay subsoil above the gravel beds of the Drift. 

 At a moderate depth we find everywhere, with few exceptions, the tough, blue 

 " boulder-clay," which usually has, in this region, a thickness of over one hun- 

 dred feet. 



Whether there was or not an outlet from the south end of Lake Michigan, 

 after the close of the Drift period, there certainly was one at that point before 

 the Drift was deposited. This valley, including that of Lake Michigan, may 

 have been excavated by a glacier; but of this we cannot be certain, without a 

 more extended examination of its bottom than will probably ever be possible. 

 The depth of this channel, in its northern part, is unknown ; its western bank 

 is seen on the Kankakee, just above Momence, where 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 Harrisburg, Pa., who also informs me that the same 

 " shoulder " of rock is found upon the Calumet, nearly due north from Mo- 

 mence. In this part of its course, passing through very solid rocks, the chan- 



*Geology of Indiana, 1859-60, pp. 201-220. 



{Proceedings of the Wabash Academy of Science, Indianapolis, 1855, p. 16. 



