BROWN COUNTY, 69 



at the mill we found the following beds overlying the blue geodiferous shales 

 of the Keokuk group : 



FEET. 



Fine grained greenish sandstone 6 



Brown shale 12 to 15 



Brown magnesian limestone 8 " 10 



In the river bluffs, about two miles southeast of Versailles, the brown mag- 

 nesian limestone, which forms the lower division of this group, is exposed in 

 the face of the bluff", and a quarry has been opened in it, showing about fifteen 

 feet in thickness of regularly bedded limestone, which forms an excellent build- 

 ing stone. This quarry is about fifty feet above the level of the Illinois bot- 

 toms. 



At LaGrange, there is from twenty-five to thirty feet of this group exposed 

 at the base of the bluff. The upper portion is a gray limestone, about 

 six feet thick, below which, there is about twenty feet, consisting of alterna- 

 tions of brown magnesian limestone, with calcareous sandstones and shales. 

 The magnesian limestone at this point, is not as evenly textured as this rock 

 usually appears, and some of the layers crumble readily, on exposure to atmos- 

 pheric influences. This group is also exposed on a small creek, five miles 

 west of LaGrange, on the Mt. Sterling road, the upper bed consisting of gray 

 concretionary limestone, while the lower part is a brown magnesian limestone, 

 about fifteen feet in thickness. The general outcrop of the St. Louis group in 

 this county, is along the valleys of Crooked creek, and McGee's creek, and on 

 some of their principal tributaries, and also along the base of the Illinois river 

 bluffs, wherever the stratified rocks are exposed. In the vicinity of Ripley, 

 we find this group outcropping in the bluffs of Crooked creek, affording, with 

 the underlying shales of the geode bed, the following section : 



FEET. 



Concretionary limestone 10 



Brown magnesian limestone 15 



Blue argillaceous shales, partly exposed 25 



The two upper beds in the above section, belong to this group, while the 

 lower, which at this locality was only partly exposed, belongs, for the most 

 part at least, to the underlying Keokuk group. The magnesian limestone, and 

 the calcareous sandstone of the St. Louis group, furnish the most durable 

 building stone to be found in the county. 



Keokuk Group. Only the upper part of this group appears above the sur- 

 face in this county, including the geodiferous shales, and a few feet in thick- 

 ness of thin bedded limestone. These beds are exposed on the lower course of 

 McGee's creek, and also on Crooked creek, along its whole course in this 

 county. At Chambersburg, the thin bedded limestone which underlies the 



