RAW MATERIAL: NATURAL-CEMENT ROCK. 



213 



West Virginia-Maryland. A wide belt of magnesian limestones of 

 Cambrian age crosses Maryland into the eastern part of West Virginia. 

 Several small natural-cement plants have been established in this district 

 at various times, particularly near Antietam, Md., and Shepherdstown, 

 W. Va. 



ANALYSIS OF NATURAL-CEMENT ROCK, ANTIETAM, 



Silica (Si0 2 ) 



Alumina (A1 2 O 3 ) 



Iron oxide (Fe 2 O 3 ). . . . 



Lime (CaO) 



Magnesia (MgO) 



Alkalies (K 2 0,Na 2 0). . 

 Sulphur trioxide (SO 3 ). 

 Carbon dioxide (CO 2 ). . 

 Water. . 



MD. 

 (l) 

 15.97 



} 7.59 



23.72 

 15.6 



n. d. 



0.71 



J34.82 



Cementation Index 1.14 



(1). Antietam, Md. C. Richardson, analyst. Brickbuilder, voL 6, p. 151. 



Wisconsin. Two plants in Wisconsin are engaged in the manufacture 

 of natural cement from a clayey magnesian limestone of Devonian age. 

 These plants are located north of Milwaukee, near the lake. The cement- 

 rock deposit is very thick, compared to most natural-cement proposi- 

 tions, a quarry face 22 feet high being worked by the Milwaukee Cement 

 Company. 



TABLE 101. 

 ANALYSES OF NATURAL-CEMENT ROCKS, MILWAUKEE DISTRICT, Wis. 



1. Mineral Industry, vol. 6, p. 95. 



2. Trans. Am. Inst. Min. Engrs.. vol. 8, p. 507. 



I: ;; :: :: :; :: :; :: ,; ;; 



5. Average of preceding four analyses. 



