GROUND WATER IN NORTH-CENTRAL TENNESSEE

126 GROUND WATER IN NORTH-CENTRAL TENNESSEE
60 feet deep hare been drilled in several places. These wells encounter
water at the upper surface of the Chattanooga shale and at random
horizons in shaly facies of the overlying Fort Payne formation.
Shaly and channeled beds of the Devonian, Silurian, and Ordovician
limestones supply drilled wells from 70 to 125 feet deep on and near
the bottom lands of the Cumberland River Valley, where the water­
bearing zone is approximately 300 to 350 feet above sea level. In the
Harpeth River Valley of the southern part of the county wells from
50 to 75 feet deep in the Silurian and Devonian limestones find rela­
tively soft water about 450 feet above sea level. The extent and
lateral persistence of the channeled zones that supply these wells
can not be inferred from the well data at hand.
The conditions under which ground water occurs in limestone are
discussed on pages 69-89. Analyses of representative ground waters
from Cheatham County are tabulated on pages 114-115.