120 GEOLOGY OF ILLINOIS. 



It is generally believed that some layers of the Buff might be burned 

 into a good hydraulic lime ; but this is not known by the test of ex- 

 periment. 



Peat. On the Killbuck creek, on section 30, in the township of Mon- 

 roe, there is a long, narrow, irregularly shaped peat bed, containing 

 about fifty acres. In the deepest parts the deposit is, perhaps, twelve 

 feet thick. The peat is the result of the decay of the usual grasses, 

 sedges and mosses, but is rather grass-peat than moss-peat. Compared 

 with the Cattail beds of Whiteside county, it is more porous, fibrous 

 and unripe. It is available already as a fertilizer, and like the rest of 

 our small, prairie, unripe beds, will some day be used largely for that 

 purpose. Its value, as a fuel, depends upon the success of the peat ex- 

 periments now being tried in many places. For a fuller discussion of 

 Northern Illinois peat, its economical uses, its value, and its future 

 prospects, I refer the reader to the report upon the economical geology 

 of Whiteside county. 



Clays and Sands. Banks of common yellow sand, suitable for mortar 

 making and plastering, may be found almost any where in the banks 

 and sand-bars of Rock river. The sub-soil clays, under the thin oak 

 soils, and in fact most of the sandy sub-soil, may be molded into a good 

 article of common red brick. 



According to all our Western geologists, the white rocks of the St. 

 Peter's sandstone furnish the very best material for the manufacture of 

 glassware. The Pittsburg glass manufactories obtain tons of their 

 sand from the saccharoidal deposits of Missouri, a rock identical with 

 our St. Peter's sandstone. Our sandstone, however, is white, pure, lim- 

 pid, and free from foreign matter ; theirs consist more of the yellow and 

 brown-stained varieties. The sugary, white sandstone of the upper 

 Mississippi is a pure silica. If the statements of the learned Dr. OWEN 

 are true, only about two-tenths of one per cent, of extraneous matter, as 

 shown by chemical analysis, enters into the composition of the snow- 

 white sands of this formation. 



Thousands of tons of the sand could be cheaply transported down the 

 river to the Eock Island coal fields ; or, when the contemplated railroad 

 up the Eock river valley is completed, for the purpose of connecting 

 the lumber regions of the north with the prairies of Iowa and coal fields 

 of Illinois, the coal could be easily run up from Eock Island to the Ore- 

 gon or Grand DeTour sand cliffs, and glassware for the whole North- 

 west be cheaply and successfully manufactured. These facilities for 

 moving the coal and sand together will exist at no distant day. It will 

 then remain for capital to invest in this remunerative branch of manu- 

 facturing industry. 



