46 DEPOSITS OF PHOSPHATE OF LIME. [bull. 46. 
[II. Apatite from Murcia, by G-. Rose.] 
Phosphoric acid (1) 42.172 
Fluorine (2) 3.434 
Chlorine (3) 0.566 
Lime 49.894 
Calcium 3. 934 
100.000 
(1) Equal to tribasic phosphate of lime 92.066 
(2) Equal to fluoride of calcium 7.049 
(3) Equal to chloride of calcium 0. 885 
PHOSPHOKITES. 
"The name phosphorite was used by Kirwan for all apatite, but in 
his mind it especially included the fibrous, concretionary, and partly 
scaly mineral from Estremadura, Spain, and elsewhere." 1 In this 
latter sense it is used here, but it will also include certain vitreous and 
earthy forms which are often so intimately associated with the above- 
mentioned varieties and which often run into them by such gradations 
that they are best described together. 
The phosphatic deposits of Nassau, in Germany* those of the south- 
west of France, commercially known as " Bordeaux phosphates," and 
those of Estremadura and Oaceres, in Spain, come under this head. 
PHOSPHORITES OF NASSAU. 
The phosphorite deposits of Nassau were discovered in 1864 by Herr 
Victor Meyer, of Limburg, though as early as 1850 Dr. Sandberger had 
discovered apatite in the manganese mines of Kleinfeld. 
The principal phosphorite deposits occupy an irregular area, bounded 
on the northeast by the town of Weilburg, on the northwest by the 
Westerwald, on the east by the Taunus Mountains, and on the south 
by the town of Dietz. The general appearance of the country is that 
of a broad plain, intersected by the Lahn and its tributaries. The 
phosphorite is found in cavities in a hard, massive, dolomitic limestone 
of the Devonian age. The following section, 2 in an ascending order, 
will show the geologic relations of the deposits : 
(1) Porphyry, dark to light gray and green, containing cavities of calcareous 
matter. 
(2) Slaty and shaly beds, much contorted. 
(3) Dark-red sandstone, containing beds of hematite. 
(4) Dolomitic limestone, white, blue, or pink in color, resting unconformably on 
the underlying bed. 
(5) Phosphorite deposits. 
(6) Brown clay, supposed to be Tertiary. 
The phosphorite is sometimes found on the surface and sometimes 
under as much as two hundred feet of clay. The hollows contain- 
ing the phosphorite are generally much worn and have all their edges 
rounded off, as if they had been exposed to the action of water for a 
long time before the phosphorite was deposited in them (Figs. 22, 23). 
1 J. D. Dana: A System of Mineralogy, 1873, p. 531. 
2 D. C. Navies: OeoL Mag., vol, 5, London, 1868, p. 262. 
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