KANKAKEE AND IROQUOISJCOUNTIES." 239 



Economical Geology. 



It is probable that enough coal will be found in the southern part of the 

 county to become largely an article of export, as well as to supply the local de- 

 mand. From the position in the Measures which the seams here to be found 

 probably occupy, it is not improbable that they may furnish the free-burning 

 "' block " coal so much sought for, for furnace use. But of this, nothing is 

 known yet. 



Limestone for building, though not of the most durable variety, can be ob- 

 tained in any quantity along the lower course of the Iroquois, in Kankakee 

 county, and can be brought in flat-boats to the center of the county. Some ef 

 the same beds will yield a good article of hydraulic lime. A strong building 

 lime can be obtained at Momence, and brought into the county very cheaply 

 by the new Chicago and Danville railroad. 



The river bottoms are, of course, well supplied with water ; and the prairie 

 portions of the southern half of the county, besides getting moderate supplies 

 by the shallow wells in the subsoil, also obtain unlimited quantities of flowing 

 water by forcing " drive wells," or sinking borings from thirty to sixty feet 

 into the sand or gravel beds which occur in the top of the boulder clay. The 

 occurrence of artesian water at so small a depth, and especially in unconsolida- 

 ted deposits, is very uncommon,. though not unknown elsewhere. The cause 

 of the phenomenon is a little uncertain. I was at first inclined to suppose that 

 the water supply came from the higher land of Central Indiana, north of the 

 Wabash ; but have concluded that that position is untenable. The only ex- 

 planation which has proved entirely satisfactory to me, is that which refers the 

 source of the water to the St. Peters sandstone, which supplies so many arte- 

 sian wells in LaSalle, Grundy, Will and Cook counties. Following the line of 

 the anticlinal axis, which runs south 33 east from LaSalle, we find that it 

 passes very near Urbana, at which place deep borings in the materials which 

 fill the old valley, before described, have found at the bottom a pure white 

 sand, closely resembling that into which the St. Peters disintegrates at its out- 

 crop. This sand, and others in contact with it, are so abundantly filled with 

 water in all this region, as to have defied all efforts to sink shafts through it; 

 and it is natural to refer the water to the artesian supply of the St. Peters. 

 If the boulder clay were continuous over the whole region, it would not be 

 likely to allow this water to ascend and escape, except from the edges of the 

 stratum ; but, as the Lake Michigan glacier must have continued to occupy 

 this valley after the disappearance of the universal glacier which covered the 

 whole country, and deposited the boulder clay over the general surface, its 

 later deposits, though of the same material, were not continuous with the earlier 



