162 GEOLOGY OF ILLINOIS. 



Clays. Some of the underclays of the different coal seams in this county, 

 will probably furnish a good material for fire brick, tile, or pottery. The clay 

 beds under the different coal seams, however, generally appear at the surface 

 only along the sides of high bluffs, or in the bottoms of deep ravines, and 

 have not been as yet, turned to economical account. Good clays for ordinary 

 brick making, are found in the beds of the Drift, under the surface soils in all 

 parts of the county. 



Building Materials. The sandstone over coal No. 1, in the northwestern 

 part of this county, has been worked to some extent as a building stone, and in 

 some instances, appears to answer the purpose well, and when a proper selection 

 is made of this material, it appears durable. The stone abutments of a bridge 

 over Indian creek, at Arenzville, just over the line in Cass county, which were 

 built for the proposed Kock Island and St. Louis railroad, are of this sandstone, 

 quarried within the limits of Morgan county, and after ten years' exposure, 

 appear as whole and sharply cut as when first laid. In some parts of these 

 beds, however, the rock seems to crumble on weathering, and should, therefore 

 be rejected as a building stone. 



The sandstone worked on Willow Branch, in section 19, township 15, range 

 11, is probably near the same geological horizon. It is very similar in appear- 

 ance, being a light brown or gray sandstone, weathering, however, to a rather 

 lighter color than that from the previously mentioned localities. It is, as has 

 been said before, quite soft and easily worked when first quarried, but is said 

 to harden on exposure. 



The limestone beds of the Coal Measures, and their use as a building mate- 

 rial, have been briefly noticed in the preceding pages. Their use has been 

 mainly local and limited, and from the restricted nature of the exposures in the 

 sides of high bluffs or bottoms of ravines, and the general inconsiderable thick- 

 ness of the strata, it seems probable that it could not well be otherwise. The 

 sandstone beds of the Coal Measures, when sufficiently resistant to atmospheric 

 influences, are likely to afford the principal home supply of building material 

 in this county. The sandstones, etc., of the St. Louis group, which outcrop in 

 this county, have also been used to some extent, but no such quarries as are 

 found in this group in the adjoining counties, have as yet been opened in Mor- 

 gan county. 



Some of the limestone beds in this county, appear suitable for the manufac- 

 ture of quick lime. Most of this article, however, is derived elsewhere, and I 

 am not aware that this manufacture has been carried on to any extent in any 

 place in the county. Sand and gravel for building purposes are sufficiently 

 abundant in all parts. 



