PHOSPHATES AND OTHER MINERAL FERTILIZERS. 
Several papers on the Tennessee phosphate industry are here pre- 
sented. Incidental references to the use of gypsum as a fertilizer 
will be found in a paper on the salt and gypsum deposits of Vir- 
ginia, on pages 406 to 416 of the present bulletin. On pages 221 to 231 
will be found a discussion of the utilization of basic steel slags for 
fertilizing purposes. 
ORIGIN AND EXTENT OF THE TENNESSEE WHITE PHOSPHATES. 
By C. W. Hayes. 
VARIETIES OF WHITE PHOSPHATE. 
In a former report on the Tennessee white phosphates the follow- 
ing classification of the deposits was adopted: (1) Stony, (2) lamellar, 
(3) breccia. 
The first variety consists of a siliceous skeleton, the cavities in which 
were originally filled with lime carbonate, but are now filled with lime 
phosphate. The latter forms from 27 to 33 per cent of the rock. This 
stony phosphate is found in considerable abundance in the northern 
part of Perry County, on Terrapin and Redbank creeks. No attempt 
has yet been made to utilize it, and unless some inexpensive method 
is devised for concentrating the lime phosphate, it is too low grade to 
compete with the other varieties. 
The third variety, the breccia phosphate, which forms most of the 
surface outcrops in the Toms Creek district, appears to be confined 
almost exclusively to the surface. Its importance is small, and it is 
questionable if it exists in sufficient quantity to justify the develop- 
ment of machinery for separating the phosphate from the chert, even 
if this separation were found to be practicable. 
Only the lamellar variety, therefore, has thus far been developed. 
Fortunately this variety, which is the highest grade and the most easily 
prepared for market, appears to be also the most abundant. Selected 
specimens of the thin plates contain 85 to 90 per cent of lime phos- 
phate. The less dense, greenish material, which is associated with the 
white and pink plates, contains some ferrous iron and runs slightly 
under 80 per cent of lime phosphate. There appears to be no difficulty, 
" Twenty .first Ann. Rept. U. S. Geol. Survey, Pt. Ill, 1901, pp. 473-485; 
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