GROUND WATER IN NORTH-CENTRAL TENNESSEE

STRATIGRAPHY 31
CRETACEOUS SYSTEM
UPPER CRETACEOUS SERIES
EUTAW FORMATION
The Eutaw formation, a coasfcal-plain deposit of Upper Creta-
ceous age, has been identified by Wade 39 about 9 miles north of the
Tennessee-Kentucky boundary in Trigg County, Ky., and thence
has been traced southward about 10 miles beyond the boundary into
Stewart County, Tenn. Throughout this distance the formation
occurs only on the crest of the divide between the Tennessee and
Cumberland Rivers. It does not occur elsewhere in the region in­
vestigated, although undoubtedly it was deposited rather generally,
for it crops out over extensive areas farther south in Wayne and
Hardin Counties, as was pointed out first by Miser.40
At the locality in Trigg County, Ky., described by Wade the
Eutaw formation consists of red micaceous sand that contains streaks
and pellets of white clay, the whole 10K feet thick. The correlation
is based upon the presence of Halymenites major Lesquereux.
As the Eutaw formation occurs only on the crest of the divide in
north-central Tennessee, it is subject to drainage by the many trib­
utary streams that flow from this upland divide and hence is not
likely to retain large quantities of ground water.
TUSCALOOSA FORMATION
The Eutaw formation at the locality in Trigg County is underlain
by at least 31 feet of gravel that Wade 41 correlates with the Tusca­
loosa formation, because of its lithologic character and its position
beneath the fossiliferous Eutaw. From this locality the Tuscaloosa
formation has been traced southward into Tennessee, its outcrop
forming a band that surrounds the Eutaw formation. Wade has also
identified the formation along the Nashville, Chattanooga & St.
Louis Railway about 2 miles east of McEwen, where there is "resting
on chert of the St. Louis formation about 30 feet of very compact
hard white chert gravel which is typical of the Tuscaloosa." Several
drilled wells in the vicinity of McEwen Nos. 163, 164, 165, and 166
(pp. 159-160) are reported to pass through 200 to 230 feefc of uncon-
solidated material before reaching solid rock. Part of this material
may belong to the Tuscaloosa formation, but the records of the wells
do not discriminate between gravel and residual chert, so that it is
impossible to estimate the thickness of the Tuscaloosa formation at
this locality. The Tuscaloosa formation caps the higher hills of an
extensive area in eastern Humphreys County and southwestern
89 Wade, Bruce, The occurrence of the Tuscaloosa formation as far north as Kentucky: Johns HopMns
Univ. Circ., new ser., No. 3, pp. 104-105,1917.
40 Miser, H. D., Economic geology of the Waynesboro quadrangle: Resources of Tennessee, vol. 4, No.
3, p. 107, Tennessee Geol. Survey, 1913.
« Wade, Bruce, op. cit., p. 104.