GROUND WATER IN NORTH-CENTRAL TENNESSEE

54 GROUND WATER IN NORTH-CENTRAL TENNESSEE
LOWER ORPOVICIAN SERIES
LEBANON LIMESTONE "
The Lowville limestone is underlain disconformably by the Lebanon
limestone, the type locality of which is the city of Lebanon,17 Wilson
County. The Lebanon limestone generally comprises many beds of
compact brittle light-gray, dove-colored, or bluish-gray limestone in
alternation with thin seams of bluish-gray or yellow clay. The layers
of limestone are from 1 to 6 inches thick, and those of clay only a
fraction of an inch. Some of the limestone beds are sandy, others
are laminated, and still others are mottled; some layers are dense and
unfossiliferous, others are coarsely crystalline; furthermore, the beds
show ripple and rill marks at many different horizons. At many
places a massive bed of drab coarsely crystalline unfossiliferous lime­
stone from 2 to 11 feet thick, very similar lithologically to the under­
lying Kidley limestone, occurs in the lower half of the formation.
The Lebanon limestone is fossiliferous at many horizons, although
some beds are barren and others are composed almost entirely of the
shells of one or several species. The most abundant and character­
istic fossils of the formation are
Plectambonites sp.
Scenidium anthonense.
Batostoma libana.
Escharopora briareus.
Leperditia fabulites.
Orthis tricenaria.
Phragmolites grandis.
Pianodema subaequata.
Pachydictya cf. P. foliata.
Pterygometopas troosti.
Rhynchotrema minnesotensis.
Chasmatopora sublaxa.
Streptelasma cf. S. parasiticum.
Zygospira saffordi.
The Lebanon limestone ranges in thickness from 80 to 125 feet and
in general thins westward. It crops out in a band from half a mile to
5 miles wide along the base of the hills that bound the Nashville
Basin peneplain in Rutherford County. It also covers extensive
areas in Davidson, Williamson, and Wilson Counties. (See pi. 4.)
The generalized form of its outcrop is an elliptical band surrounding
the Nashville dome. (See pp. 62-63.) The formation is not known to
crop out in the Wells Creek Basin of Stewart County. (See p. 191.)
RIDLEY LIMESTONE
The thin-bedded Lebanon limestone is underlain, in seeming con­
formity, by the Ridley limestone, the type section 18 of which extends
half a mile southward from the Davis mill (formerly Ridley's mill),
i* This discussion of the Lebanon limestone and the underlying formations of the Stones River group is
adapted in large part from Galloway, J. J., Geology and natural resources of Rutherford County: Tennessee
Geol. Survey Bull. 22, pp. 32-45,1919.
w Saflord, J. M., and Klllebrew, J. B., The elements of the geology of Tennessee, p. 125, Nashville, Poster
6 Webb, 1900.
w Saflord, J, M., The geology of Tennessee, p. 261,1869.