PIKE COUNTY. 39 



found separating the strata of limestone at Nauvoo, Keokuk, and other north- 

 ern localities, were not observed here, and hence in its outcrop it is not readily 

 distinguished from the Burlington rock, except by a critical examination of the 



fossils which it contains. 



The St. Louis group, although quite limited in this county, both in its devel- 

 opment and outcrop, furnishes some excellent building stone. About a mile 

 and a-half northwest of Perry, there is an outcrop of about eighteen feet in 

 thickness of massive, brown, magnesian limestone, that, for culverts, bridge 

 abutments and foundation walls, especially where the rock is to be subjected to 

 the combined action of frost and moisture, has no superior in the State. It 

 contains considerable iron, which oxydizes freely, and gives to the surface a 

 rusty brown color, which unfits it for use in the outside walls of fine buildings, 

 where a pleasing exterior is desirable, but for all other uses it is a valuable and 

 durable stone. This limestone was also met with just on the north line of the 

 county, immediately north of Perry Springs, where a portion of the bed pre- 

 sented the same general character as at the locality above mentioned. It was 

 only seen in the extreme northern portion of the county, in township 3 south, 

 ranges 2 and 3 west. 



Coal. The coal deposits of this county are limited in their extent, and at 

 all the points where coal has been found, with a single exception, the seams 

 have proved to be too thin to be worked, except by the process of "stripping" 

 or throwing off the overlying material, and working out the coal in open trenches. 

 There are probably a good many points in the county where this may be done 

 to advantage, in the valleys of the small streams where the coal seams outcrop, 

 but the completion of the railroad from Naples to Hannibal will give access to 

 the heavy coal seams east of the Illinois river, and thus supply the demands 

 of this county for coal, at cheaper rates than could be done from the limited 

 deposits within the county. At Huntley's mine, in the northwestern part of 

 the county, the coal is six feet thick, and is worked by tunneling into the out- 

 crop, for the supply of the adjacent region, but for reasons given on a preced- 

 ing page, we are inclined to regard this as a local deposit, that will soon be ex- 

 hausted. With this single exception, there is no coal known in this county 

 that averages two feet in thickness over any considerable area, and the general 

 range is only from sixteen to twenty inches. 



Minerals. No ore of any kind, except iron, was met with in the county. 

 Carbonate of iron, as well as the bi-sulphuret, is found in the Coal Measures, and 

 the former is a valuable ore for the production of iron, where it is sufficiently 

 abundant, but no deposits of these ores were found in the county of sufficient 

 thickness to justify the expenditure of capital or labor in attempts to develop 

 them. 



