FILLMOKE COUNTY. 299 



Galena limestone.) 



ded rock that is very useful for an ornamental cut-stone. This is seen ii> 

 some of the quarries a mile or two east of Spring Valley, where it is diffi- 

 cult to assign the beds either to one horizon or the other. A short distance 

 farther east the well characterized lithology of the Trenton appears. The 

 lead ore, moreover, which has given name to the Galena, is not confined to 

 that formation. It is found to some extent both in the characteristic Galena 

 and in the underlying more compact strata, though in neither to that extent 

 that will warrant sanguine expectations. 



The principal exposures of the typical Galena in the county are on Bear 

 and Deer creeks, and on the south branch of Root river. At J. Shumaker's 

 quarry, one mile east of the valley, about eight feet of the bedding are ex- 

 posed. The layers here are of a finer and more uniform texture, and are 

 associated with shales. When cut for building they are much whiter than 

 the stone obtained at Mr. Allen's at Spring Valley. Inconsiderable quanti- 

 ties of galena are obtained at Spring Valley. No systematic exploration, 

 however, has been undertaken, the pieces found being at or near the sur- 

 face. It has been found at a number of other points in the county. 



There is a weathered exposure of the Galena on land owned by Mr. 

 Harris, N. W. J sec. 26, Sumner. This outcrop fairly presents the typical 

 lithologicai features that characterize the formation. By the Galena char- 

 acters are meant a yellowish, or buff, limestone, vesicular, crystalline, in 

 heavy layers, even on weathered bluffs, having usually a very rough exterior 

 in consequence of atmospheric destruction of the looser portions. When 

 these looser portions are removed, the surface of the rock presents a pitted 

 aspect, becoming covered with thimble holes, and depressions of all shapes, 

 with angular knobs and excrescences separating them, the whole overgrown 

 with lichens. The exposure here shows perpendicularly about twelve feet, 

 in layers from one to four feet thick, piled up on either side of the road in 

 detached mounds, like bridge abutments from which the roadway has been 

 removed. The "lead fossil", Receptaculites, appears in these layers. 



The following is the composition of the Galena burnt for quicklime at 

 Lime City, sec. 9, Spring Valley. 



Oxide of iron, - .73 



Calcium carbonate, 70.53 



Magnesium carbonate, - - 23.49- 



Silica, &c., - 4.67 



99.32 



