202 



CEMENTS, LIMES, AND PLASTERS. 



tages mentioned above that the important natural-cement-producing 

 districts are correspondingly few. According to the United States 

 Geological Survey Report for 1903 there were 65 natural-cement plants 

 then in operation. Of these 20 were in New York State, 15 in the 

 Louisville district of Indiana and Kentucky, 7 in the Lehigh district 

 of Pennsylvania, 4 in Maryland, 3 in the Utica district of Illinois, 2 each 

 in Georgia, Kansas, Minnesota, Ohio, Texas, Virginia, and Wisconsin, 

 and 1 each in North Dakota and West Virginia. This suffices to show 

 the extent to which the American natural-cement industry has become 

 concentrated in certain favorable localities. 



Georgia. Two natural-cement plants are located in northwest 

 Georgia, but they use cement rocks from two different geological forma- 

 tions, and their raw materials and products differ widely in composition. 



The plant of the Chickamauga Cement Company is located at Ross- 

 ville, Ga., a few miles south of Chattanooga. The raw material used 

 is a thin-bedded slaty limestone of Chickamauga (Ordovician) age, 

 which is here exposed over a considerable area. In geologic age, as 

 well as in chemical composition, this rock is quite similar to the cement 

 rock of the Lehigh district of Pennsylvania, but the Georgia deposit 

 is not so thick as in that region. These shaly limestones outcrop at 

 many points in northwest Georgia and northern Alabama, but so far 

 have been utilized for natural cement only at the Rossville plant. 



The second plant, that of the Howard Hydraulic Cement Company, 

 is working on limestones of quite different character. 



The Conasauga formation of the Cambrian is described by Dr. C. W. 

 Hayes as being "normally composed at the base of thin limestones 

 interbedded with shales, then of yellowish or greenish clay shales, and 

 at the top of calcareous shales, grading into blue seamy limestones". 



The Western and Atlantic Railroad, now operated under lease by 

 the Nashville, Chattanooga and St. Louis System, crosses the outcrop 

 of these rocks from above Adairsville to within a mile of Kingston. 

 At one point near the southern end of this belt limestone obtained 

 from beds lying near the top of the Conasauga formation has long been 

 utilized in the manufacture of natural cement at the plant of the Howard 

 Hydraulic Cement Company, at Cement, Bartow County, Ga., about 

 two miles north of Kingston. 



In the low ridge east of the railroad at Cement station a section of 

 these Conasauga limestones has been measured by Spencer.* 



The Paleozoic group of Georgia, p. 100. 



