210 



CEMENTS, LIMES, AND PLASTERS. 



works its cement rock by quarrying methods, stripping off the over- 

 lying limestones; but the plants at Akron all obtain their raw mate- 

 rial by mining. 



TABLE 96. 

 ANALYSES OF NATURAL-CEMENT ROCKS, AKRON-BUFFALO DISTRICT, NEW YORK. 





* Called "silica, clay, and insoluble silicates". 



1. G. Steiger, analyst. Bulletin 168, U. S. Geol. Survey. 



2. Lathbury and Spackman, analysts. 



3. E. Boynton, analyst. Gillmore, "Limes, Cements, and Mortars", p. 125. 



4. Average of analyses 1 and 2. 



I am informed by Mr. Uriah Cummings, of the Cummings Cement Co., 

 Akron, N. Y., that none of the analyses given in Table 96 are really repre- 

 sentative of the Akron natural-cement rock. The analyses are presented, 

 therefore, subject to this criticism. 



North Dakota. The single natural-cement plant operating in this 

 state is located about ten miles east of Milton, Cavalier County. The 

 rock used is a soft, chalky limestone of Cretaceous age and outcrops 

 in a bluff several hundred feet high. At present, however, only a 

 10-foot bed is being worked, by mining. (See Table 97.) 



Ohio. Small natural-cement plants have been established at vari- 

 ous points in Ohio, those at Defiance and New Lisbon being worthy 

 of some notice. The Defiance plant used a black calcareous shale 

 of Devonian age. If published analyses be correct (see Nos. 1 and 2 

 in Table 98) this rock is by far the most argillaceous material used 

 anywhere for this purpose. 



Pennsylvania. A fairly large production of natural cement has 

 always been maintained in the Lehigh district of eastern Pennsylvania, 

 though at present natural-cement manufacture there is merely inci- 

 dental to the great Portland-cement industry of the district. 



The analyses given in Table 99 purport to be representative of the 

 rock used at various Lehigh district natural -cement plants. It is hardly 



