THE NONMETALLIO MINERALS, 



263 



flint is given. Thouj>h a common rock in miiny parts of Europe, it is 

 known to American readers mainly for its occurrence in the form of 

 high clifl's along the English coast, as near Dover. Until within a 

 few years little true chalk was knoM'n to exist within the limits of 

 the United States. According to Mr. R. T. Hill ' there are, however, 

 extensive beds, sometimes 500 feet in thickness, extending throughout 

 the entire length of Texas, from the Red River to the Rio Grande, and 

 northward into New Mexico, Kansas, and Arkansas. These chalks in 

 many instances so closely simulate the English product, both in phys- 

 ical properties and chemical composition, as to l)e adaptable to the same 

 economic purposes. The following analyses from the report above 

 alluded to serve to show the comparative composition: 



Constituents. 



Carbonate of lime 



Carbonate of magnesia 



Silica and insoluble silicates 



Ferric oxide and alumina 



Phosphoric acid, alumina, and loss. 



Chloride of sodium 



Water 



Lower 

 Cretace- 

 ous 



chalk, 



Burnet 

 County, 



Texas. 



92.42 



1.38 



1.59 



.41 



Upper 

 Cretace- 

 ous 

 chalk, 

 Rocky 

 Comfort, 

 Arkan- 

 sas. 



88.48 



Trace. 



9.77 



1.25 



White 

 Cliff 

 chalk, 

 Little 

 River, 

 Arkan- 



94.18 

 1.37 

 3.49 



1.41 



White 

 chalk of 

 Shore- 

 ham, Sus- 

 sex, Eng- 

 land. 



98.40 



1.10 



.18 



.55 



100 



Gray 

 chalk. 

 Folk- 

 stone, 

 England. 



94. 09 



.31 



3.61 



Trace. 



1.29 



.70 



100 



Chalk is used as a fertilizer, either in its crude form or burnt, in the 

 manufacture of whiting (Specimen No. 264!)9, from Trego County, 

 Kansas), in the form of hard lumps by carpenters and other mechanics, 

 and in the manufacture of crayons (Specimen No. 62063, U.S.N.M.). 

 Washed, chalk (Specimen No. 62085, U.S.N.M.) is used to give body to 

 wall paper; as a whitewash for ceilings; as a thin coating on wood 

 designed for gilding, being for this purpose mixed wdth glue; to vary 

 the shades of gray in water-color paints, and as a polishing powder for 

 metals. "^ 



Concerning the importation and uses of chalk, Williams states:^ 



Paris white is the name given to the white coloring substance prepared by grinding 

 eliffstone, a variety of chalk or limestone which is as hard as some building stones and 

 has a greater specific gravity than the ordinary chalk. It is imported from Hull, Eng- 

 land, and sells at from $2 to 1-1 per ton ex vessel, according to freight rates from Hull. 

 During the calendar year 188-4 3,905^ tons of eliffstone were imported at New York. 



The paris white made in this country is sold at from $1.10 to $1.25 per hundred- 

 weight, in casks, according to make and quality. The paris white made in England, 

 of which 508,185 pounds were imported at New York during the calendar year 1884, 



^ Annual Report of the Arkansas Geological Survey, II, 1888. 

 ■■' Mineral Resources of the United States, 1883-8-t, p. 930. 



