Pliosphate Roch in Tenjiessee. — Saffovd. 26B 
showing eross-stratification. It gets its name from the fact 
that it supplied the rock for the building of the capitol at 
Nashville. Its grains are the fragments of comminuted 
■shells, corals, etc., the whole once a drifted calcareous sand; 
hence its laminar structure and cross-stratification. Average 
thickness ma}^ be placed at about 60 feet. 
3d. The DoKe Limestone, a series 10 to 12 feet thick of 
mostly a compact, dove-colored limestone. 
4th. Upon the Dove lies another division 28 feet thick, 
recently designated the Ward Limestone. Parts of this are 
much like the Capitol, laminated and showing current action. 
All of these are more or less phosphatic. but it is the Capi- 
tol division or horizon which is the great source of the phos- 
phate. Parts of this limestone show upon analysis from 15 to 
25 per cent, of phosphate, the dark lines marking the lamina- 
tion of the rock being especially rich. Throughout middle 
Tennessee, wherever the limestone has been subjected to the 
proper leaching conditions, residual fragments of phosphate 
may be found, the pieces often hioking like sandstone, or like 
porous chert. About Mt. Pleasant the original limestone 
appears to have been especially rich in phosphate, though 
other localities may be discovered as good. 
The Orthis bed lies under the masses of the leached out 
phosphate, and its outcrops, rich in Orthis shells, are a guide 
to them. 
The Ward division, t!ie 4tli of vhe series above, also yields 
locall}'' noteworthy quantities of phosphate, as does also the 
upper part of the Orthis bed. 
As to origin of the phosphate in the original limestone, J 
can say but little. No theory presents itself that is satisfac- 
tory. A few specimens of Lingula and a few forms of shells 
allied to Cyclora have been observed to which may be added 
forms referable to conodonts. What a microscopical exam- 
ination will reveal remains to be seen. The presence, accu 
mulation and sorting of the phosphate would appear to have 
something to do with the currents that existed in the ocean 
when the matter of the rocks was undergoing (lci)()sitinn. 
We have said that the dark lines marking the lamination of 
the rock and due to the currents iire especiall}'^ rich in phos- 
phate. These lines or seams, sornd in)cs jinlf an inch thick. 
