Stockdale: Stylolites 



37 



The Salem limestone is especially pure, the percentag-e ol 

 calcium carbonate running very high — from 92 to 98 per cent, 

 usually above 95 per cent. The percentage of insoluble con- 

 stituents, organic matter, silicates, etc., is very low. The per- 

 centage of magnesium carbonate, when present, is always very 

 low. A general conception of the composition of the Salem 

 limestone can be gained from the following analysis of a 

 sample taken from the quarry of the Perry Stone Company, 

 Ellettsville district, Monroe County: 



Calcium carbonate (CaCOs) 97.27 per cent 



Magnesium carbonate (MgCOs) 89 



Alumina (AI..O3) 33 



Ferric oxide (Fe^Os) 59 



Silica (SiO,) 1.00 



100.08 



(Analysis made by Illinois Steel Co.)^ 



The quarrying of the Salem limestone in Indiana is con- 

 fined mainly to two counties, Monroe and Lawrence. These 

 tAvo counties are conveniently divided into the following quar- 

 rying districts :^ 



Monroe County — 



a. Stinesville district. 



b. Ellettsville district. 



c. Hunter Valley district. 



d. Blooming-ton district. 



e. Sanders district. 



/. Belt district, between Clear Creek and Harrodsburg. 

 Lawrence County — 



a. Peerless district. 



b. Buif Pvidge district. 



c. Reed Station district. 



d. Dark Hollow district. 



e. Bedford and A'icinity. 



Mitchell Limestone 



Overlying the Salem limestone is a series of limestones of 

 varying texture, appearance, and geologic age, called the 

 Mitchell. In thickness it varies from 200 to 400 feet. Diffi- 

 culty is found in separating the lithologic formation into its 



^ For tables of chemical analyses of the Salem limestone, reference should he made 

 to: Blatchley, R.S., 1908, pp. 315, 329, 358, 366, 376, 382. 415. 



5 For the latest detailed description and maps of the quarryinc: districts, reference 

 should be made to: Blatchley, R.S., 1908, pp. 356-451. 



