04 CEMENTS, LIMES, AND PLASTERS. 



OKLAHOMA. Gould, C. N. Oklahoma limestones. Stone, vol. 23. 



pp. 351-354. 1901. 



PENNSYLVANIA. Frear, W. The use of lime on Pennsylvania soils. Bulle- 

 tin 61, Penna. Dept. Agriculture, 170 pp. 1900. 



SOUTH DAKOTA. Todd, J. E. The clay and stone resources of South Dakota, 

 Eng. and Mining Journal, vol. 66, p. 371. 1898. 



TENNESSEE. Cotton, H. E., and Gattinger, A. Tennessee building- 



stones. Vol. 10, Reports Tenth Census, pp. 187, 188. 

 1884. 



Keith, H. Tennessee marble. Bulletin 213, U. S. Geol. 

 Survey, pp. 366-370. 1903. 



TEXAS. Dumble, E. T. Building and ornamental stones of Texas. 



Stone, May, 1900. 



VERMONT. Perkins, G. H. Report on the marble, slate, and granite 



industries of Vermont. 68 pp. Rutland, 1898. 

 Perkins, G. H. Limestone and marble in Vermont. Rep. 

 Vermont State Geologist for 1899-1900, pp. 30-57. 1900. 

 Ries, H. The limestone quarries of eastern New York, 

 western Vermont, Massachusetts, and Connecticut. 

 17th Ann. Rep. U. S. Geol. Survey, pt. 3, pp. 795-811. 

 1896. 



WISCONSIN. Buckley, E. R. Building and ornamental stones of Wiscon- 



sin. Bulletin 4, Wisconsin Geol. Survey, 500 pp. 1898. 



WYOMING. Knight, W. C. The building-stones and clays of Wyoming. 



Eng. and Mining Journal, vol. 66, pp. 546-547. 1898. 



Shells as sources of lime.* Most molluscan shells consist essen- 

 tially of lime carbonate, with commonly very small percentages (less 

 than 1 per cent) of magnesium carbonate, and traces of alkalies, 

 phosphoric acid, etc. The analyses given in Table 31 will serve to 

 illustrate the composition of the shells of three common species of 

 molluscs. 



These analyses show that in ordinary practice an oyster-shell may 

 be expected to contain, as its principal impurities, several per cent 

 of organic matter and from a trace to 5 per cent of silica, iron oxide, 

 and alumina. The amount of these last clayey impurities present will 

 doubtless vary with the cleanness of the shell, as it is probable that 

 they are in large part purely external impurities. 



* Brown, L. P., and Koiner, J. S. H. Analysis of oyster-shells and oyster-shell 

 lime. American Chemical Journal, vol. 11, pp. 36-37. 1889. 



How, Dr. On the comparative composition of some recent shells, a Silurian 

 fossil shell, and a Carboniferous shell limestone. American Journal of Science 

 2d series, vol. 41, pp. 379-384. 1866. 



