122 TEANSACTIONS OF THE ILLINOIS 



fantastic shapes at Deer Park and Starved Rock, a little to the northeast; but at 

 LaSalle, a few miles southwest, coal pits are sunk for hundreds of feet, and the black 

 treasures of the earth found in the greatest abundance. At Sublette the Galena lime- 

 stone is the bed rock nearest the surface; but at Princeton, towards the south and 

 west, an artesian well, five hundred feet deep, still exhibits coal measure deposits. 

 This shows that this old Silurian Beach, in the carboniferous ages of the world, 

 presented the appearance of a somewhat abrupt range of hills across that part of the 

 State. 



Over that part of the country north of this Beach, the bed rocks are covered with 

 superficial deposits from ten to fifty or one hundred feet in thickness, composed of 

 clays, sands, loams, gravels, drift materials, and prairie soils of later growths. If this 

 superincumbent mass should all be removed, leaving the naked bed rocks, the general 

 iiice of the country as to levelness of appearance, would not vary much from the 

 present state of things. 



In classifying the soils in this Rock river district, we find several well marked varie- 

 ties . The alluvial deposits of the river bottoms are latest in formation, and deserve a 

 brief notice. In examining river deposits, the first thing worthy of consideration is 

 thejlood led. Here the action of the river is that of currents, or flowing water. 

 Where the current runs strong, sand will be thrown up in tow heads and sand banks 

 and sand islands; in the still places a fine black mud will be deposited; and this force 

 will exert a sifting and assorting influence, and form mud flats and banks, and dei^osits 

 of pure sand. The next action of the river will be over its ^f-ood plain, or that part of 

 its bed covered only by the high water of the spring inundations. This is usually a 

 low bottom, covered at the flood of the river with water, and producing a heavy crop 

 of sour prairie grass later in the season. Over this the water usually rises and falls 

 without much current action, and a yearly Nile-like detritus, or fine mud, is jirecipi- 

 itated. The soil thus formed is fat, deep, and sour, and is unfit for agricultural and 

 Horticultural purposes, until it has been built up beyond the influence of the river 

 floods, and sweetened by the sun and atmospheric influences. Then it becomes a soil 

 of inexhaustible richness and productiveness. 



Stepping backwards in geological time,, we next come to the old river terraces, 

 which are simply the ancient flood-beds and flood-plains of these same rivers, at a time 

 when they rolled an infinitely larger volume of water to the sea. Over these are the 

 sandy soils and the rich, flat bottom lands, Nile-like in their inexhaustible produc- 

 tiveness. The Mississippi River, Rock River towards its mouth, and many of the 

 smaller interior streams present these well known river phenomena; and make a notice 

 of these alluvial deposits and this fluviatile action necessary in speaking of the soils of 

 the State. 



Receding backward in geological time, we come to the bluff fonnations, the oldest 

 deposits of the Quaternary system. This is called the Loess, or Bluff formation. It 

 is not extensively developed in Northern Illinois, but is present in most of the blufl's 

 which skirt our streams. Deep rooting trees and vines find in it a congenial soil, and 

 the best soil conditions of growth. Some of these Loess or partly Loess formations 

 in our part of the State would be the best fruit and wine producing districts in the 

 world if kindly Italian skies and genial atmospheric conditions smiled on the tops of 

 the trees and vines. When the Mississippi and the Illinois rivers were lake-like in 

 their expanses, and the waves beat up against theu- blufl shores, throwing up silt, 



