108 Th( American Geologst. February, issh 
two beds or strata containing such material, one immediately 
above the Black shale and the other immediately below it. 
That above the shale is a bed made up more or less of gray- 
ish, rounded, concretionary masses, named, in the writer's 
notes, ••balls'* and "kidneys."" These have been long known to 
be quite rich in phosphate, and search has been made for the 
localities where they occur most abundantly. Some of the 
masses yield from 50 to 65 per cent, of phosphate (Ca 3 2PO, ). 
the other constituents being calcium carbonate, the oxides of 
alumina and iron, silica and organic matter. When broken 
the interior often has a granular, open structure, and now and 
then exhibits fossils, chiefly individuals of a species of Lin- 
gula. "When struck with a hammer they give off a fetid odor. 
The bed below the shale has been less studied. Its weath- 
ered outcrop has the appearance of a yellowish sandstone and 
may often be seen on the slopes of many valleys in the great 
highland region southwest from Nashville. Of late it has 
been found to yield locally a very promising percentage of 
phosphate, and investigations are now going on looking to its 
full development. The analyses so far made indicate the 
presence, in some samples, of as much as 50 to 7<> per cent., or 
more, of phosphate. The more complete results will be given 
hereafter. At certain points the bed contains fish teeth and 
fragments of bone, having the appearance of a bone bed. It 
also shows occasionally indications of a coprolitic origin. 
The generalized section below, in descending order, made 
from many observations taken in Maury and Lewis counties, 
will serve to illustrate the relation of the two phosphate-bear- 
ing beds to the Black shale and other associated formations. 
Section in Maury and Leu-is counties, Tenn. 
1. Harpeth shale; light blue shale; base of Sub-carboniferous or 
Mississippian. 
2. Bed of concretionary musses, of spherical, kidney- and cake- 
shaped forms, containing phosphate. These vary in size from that of 
pigeons' eggs to forms as large as a man's head, and larger. The masses 
are found in a persistent stratum immediately above the Devonian 
Black shale, sometimes loosely disposed in a greenish or bluish shale, 
and sometimes tightly packed together in a bed twelve or more inches 
in thickness. Ordinarily the bed has less thickness, but, thick or thin, 
it may be said to be universally present, its "kidneys" serving to in- 
dicate the place of the Black shale, when the latter is covered or want- 
ing. 
