RAW MATERIAL: NATURAL-CEMENT ROCK. 



205 



Kansas. The natural-cement district of Kansas is located around 

 Fort Scott, where a 4^-foot bed of natural-cement rock outcrops. The 

 rock is a dark-colored, fine-grained, compact limestone of Carboniferous 

 age. It extends for a considerable distance throughout the State, but 

 as yet has been worked for natural cement only in the immediate vicinity 

 of Fort Scott. 



TABLE 90. 

 ANALYSES OF NATURAL-CEMENT ROCK, FORT SCOTT, KANSAS. 



1. Smith, Mineral Industry, vol. 1, p. 49. 



2. Brown, "Cement Directory", 2d ed., p. 276. 



3. Richardson, Brickbuilder, vol. 6, p. 151. July, 1897. 



4. Average of preceding analyses. 



Maryland. The natural-cement industry of Maryland has been 

 carried on in three separate areas. One of these areas including the 

 old plants at Antietam and Shepherdstown will be described later 

 under the heading of West Virginia-Maryland. The other two areas 

 include respectively the plants at Cumberland and Potomac in Alle- 

 gany County, and that at Round Top or Hancock in Washington 

 County. In both of these areas the limestones used are of the same 

 geologic age, and approximately of the same composition, so that they 

 will here be described together. Analyses are given in Table 90. 



In geologic age the natural-cement rock of the Cumberland-Han- 

 cock district corresponds closely to that used in the various New York 

 districts, being assigned by geologists to the Salina group of the Silurian. 

 It is a shaly limestone, varying in color from dark bluish gray to dull 

 black. In the Cumberland area it is exposed in four beds of sufficient 

 thickness to be worked, these cement-beds being separated by shales 

 and limestones. The separate beds vary from 6 to 17 feet in thickness. 



Minnesota. Two natural-cement plants are in operation in Minnesota. 

 One of them is located at Mankato, Blue Earth County, and uses a 

 limestone of the Lower Magnesian (Ordovician) series. The analyses 

 (Table 91) of the raw material used at this plant have been published. 



