GROUND WATER IN NORTH-CENTRAL TENNESSEE

STRATIGRAPHY 53
Dystactospongia minor, has long been correlated by Ulrich and Bassler
with the Lowville limestone of New York. Recently Bassler 10 has
correlated this member with the "Tyrone formation" of Miller u in
central Kentucky. It is generally present on the north and east
flanks of the Nashville dome but according to Bassler is absent on the
west flank. The lower member of the Lowville limestone is generally
present on all sides of the Nashville dome. It is correlated by Bassler
with the "Oregon formation" of Miller in central Kentucky 12 and
with the beds originally called Carters limestone, from the basin of
Carters Creek, 13 a tributary of the Duck River in central-northern
Maury County. This member is here designated the Carters lime­
stone member of the Lowville limestone, which is a restriction of the
name Carters as heretofore used. The member is somewhat more
earthy on the west side of the Nashville dome than on the east.
Nelson M has identified a bed of greenish sticky clay or bentonite 21
inches thick and 8 feet below the top of the Lowville limestone at
Singleton, Bedford County, about 50 miles southeast of Nashville.
He has also identified the same stratum tentatively in the vicinity of
Nashville and as far north as Highbridge, Ky., and as far south as
Birmingham, Ala. Its maximum known thickness is 10 feet, near
Highbridge. This bentonite is classified by Larsen as a decomposed
volcanic ash.
The Lowville limestone ranges from 40 to 110 feet in thickness in
north-central Tennessee, though it is commonly about 65 feet thick;
its lower member, the Carters limestone member, is 40 to 60 feet thick
in its type locality. The Lowville limestone crops out in an irregular
band along the middle slopes of the hills that surround the Stone
River Basin in Rutherford County and southeastern Wilson County
and is widely distributed in the valley of the Cumberland River as far
downstream as Nashville. It also crops out over a large area in the
valley of the Harpeth River, where it extends downstream within 1%
miles of Franklin. Northwest of the Nashville Basin, in the Wells
Creek Basin of Stewart County, the Lowville limestone also crops out,
overlain by limestone of probable Hermitage age and underlain by
limestone of Beekmantown(?) age. 15 (See p. 191.) Both the upper
and lower contact zones are concealed in that area.
" Bassler, R. S., op. cit., p. 64.
11 Miller, A. M., The lead and zinc-bearing rocks of central Kentucky: Kentucky Oeol. Survey Bull. 2,
pp. 14-16.1906.
«Idem, pp. 13-14.
« Safford, J. M., The geology of Tennessee, p. 263,1869. Hayes, O. W., and Ulrich, E. 0., U. 8. Qeol.
Survey Oeol. Atlas, Columbia folio (No. 95), p. 1,1903.
M Nelson, W, A., Volcanic ash bed in the Ordovidan of Tennessee, Kentucky, and Alabama: Oeol. Soc.
America Bull., vol. 33, pp. 605-615,1922.
15 Ulrich, E. O., Revision of the Paleozoic systems: Oeol. Soe. America Bull., vol. 22, p. 671,1911.