124 GEOLOGY OF ILLINOIS. 



Limestone for Lime. Many of the limestone beds of the Niagara group, in 

 this district, afford a good material for the manufacture of lime, and have been 

 worked for this purpose. Lime kilns have been established at Naperville and 

 other places in DuPage county, and at several points along the Fox river, in the 

 vicinity of the towns of Aurora, Batavia, Geneva, and St. Charles, in Kane 

 county. In northern DeKalb county, the outcropping beds of the Galena 

 limestone have been used for the same purpose, and are reported to have fur- 

 nished a good article. The deposit of calcareous tufa, three miles north of the 

 city of Elgin, and its former manufacture into lime, have been already men- 

 tioned in the earlier part of this chapter. 



In the lowest part of the Niagara group, at Fayville, on the Fox river, about 

 four miles north of St. Charles, there occurs a stratum of somewhat argillaceous 

 magnesian limestone or dolomite, which it is reported has been tried and found 

 to answer for the manufacture of hydraulic cement. An analysis of this rock, 

 by Dr. Blaney, may be found in the appendix to the third volume of these Re- 

 ports. Beyond this I am not aware of any material which has been tested for 

 this purpose, within the limits of this district. 



Other Building Materials. Clay and loam suitable for the manufacture of 

 brick may be obtained from the Drift and surface deposits in various parts of 

 this district. The best material .for this purpose, however, is found in the 

 northern part of Kane county, at the village of Dundee. The clay here, 

 which appears to belong to the Drift formation, is quite free from oxydes of 

 iron, and burns into brick of a delicate pale yellow color, in assorted lots, not 

 inferior in appearance to the celebrated Milwaukee brick. In other places, 

 however, the same difficulty is met with as in Cook county ; the clay contains 

 too great a proportion of lime to produce at once a handsome and durable 

 article of brick. Sand and gravel for mortar and concrete are sufficiently 

 abundant in all parts of the county. 



The limestone boulders and hard-heads, which are so abundant in various 

 places along the Fox river, in Kane county, are also used to a limited extent as 

 a building material, in ornamenting the fronts of houses, etc. 



Peat. Deposits of this material, of greater or less extent, are found in vari- 

 ous parts of this district, but are most numerous and extensive in the northern 

 portion of Kane county, where there are some rather extensive level, wet prairies. 

 But little attention, however, has as yet been paid to the economical value of 

 this material, and the depth and extent of the deposits have been scarcely tested. 

 At the village of Carpenterville, on the Fox river, one mile north of Dundee, 

 there is a deposit of peat one hundred acres or more in extent, and averaging at 

 least four or five feet in depth, which has been somewhat used in the neighbor- 

 hood as fuel, and found to answer well. Still more extensive beds occur farther 



