GROUND WATER IN NORTH-CENTRAL TENNESSEE

STRATIGRAPHY 47
and the adjacent part of Maury County. In the type region the
complete section comprises eight members, as follows:
Section of the Leipers limestone in the type region
[Hayes, C. W., and Ulrich, E. 0., op. eit., p. 2]
Unconformity. Feet
Earthy blue limestone, dense in fresh exposures but weath­
ering knotty; current-bedded, inasmuch as its only com­
mon fossil, Platystrophia lynx, is generally waterworn;
may be absent.
Soft calcareous light-blue shale, which occurs at very few
localities. This is the horizon of the branching bryozoan
Bythopora gracilis (Nicholson), which is very abundant in
the vicinity of Cincinnati-_-_______________ Thin or absent.
Earthy limestone and calcareous shale, widely distributed;
contains Orthorhynchula linneyi and Tetradium fibratum
and is very similar lithologically to several beds in the
underlying Catheys formation which hold the same spe­
cies; thickness not more than_______________________ 7
Knotty impure limestone and shale, blue and gray; ex­
tremely fossiliferous, monticuliporoid Bryozoa being
especially abundant. Of more than 50 species of fossils,
the most characteristic are Amplexopora columbiana,
Homotrypella nodosa, and Strophomena planoconvexa._.__. 5-12
Granular crystalline gray limestone, sandy at some places,
slightly phosphatic, and sparingly fossiliferous. Maxi­
mum thickness more than____________________________ 40
Thin-bedded, shaly limestone which is extremely fossilifer­
ous. Of the fossils, the most diagnostic are a long, hinged
form of Platystrophia laticosta, a species of Hindia, and
several undescribed bryozoans._______________________ 6-14
Mottled crystalline limestone which contains shells of Cteno-
donta, a large branching Escharopora, and a small ramose
bryozoan (Bythopora) ; not present in all sections. Maxi­
mum thickness.___________________________________ 20
Shale and thin-bedded limestone, of which an undetermined
species of Bucania or Salpingostoma is characteristic.
Maximum thickness_________________________________ 10
Catheys formation or Cannon limestone.
Elsewhere in north-central Tennessee, however, these eight mem­
bers can not always be differentiated; at one locality the entire for­
mation may be knotty earthy limestone, and at another it may be
granular crystalline limestone. The upper half of the Leipers lime­
stone contains deposits of rock phosphate at three horizons, each of
which has been the scene of mining activity at one or more points in
the central basin. These deposits have been described by Hayes and
Ulrich.96
Ulrich 97 has concluded that the fauna of the Leipers formation,
which is of undoubted Upper Ordovician (Maysville) age, is very
« Hayes, C. W., and Ulrich, E. 0., op. cit., p. 5.
n Ulrich, E. 0., Revision of the Paleozoic systems: Qeol. Soc. America Bull., vol. 22, pp. 299-300,1911,