GROUND WATER IN NORTH-CENTRAL TENNESSEE

MONTGOMERY COUNTY 163
Driller's log of J. T. Anderson wttt No. 1
(No. 185, pi. 4, Test well drilled by Tennessee Central Oil Co. in 1921. Casing head approximately 525
feet above sea level]
Feet
Soil, __________________________________________ 0-5
Limestone, dense, blue_______________________ 5-30
Shale, black (Chattanooga shale)________________ 30-50
Sandstone (?) hard, gray_________________________ 50-245
Limestone and shale, dark blue-gray_____________ 245-260
Limestone, pink____________.______ 260-370
Limestone, white______________________________ 370-375
Limestone and green shale, alternate thin beds______ 375-400
Limestone, white______________________________ 400-420
Limestone, pink_______________________________ 420-470
Limestone, brown, dense_________________________ 470-500
Shale, green, soft ____________________ 500-504
Shale, brown, hard_________-___________-_-______ 504-540
Limestone, gray, cherty________________________ 540-590
Limestone, black, sandy and cherty _________ _ ___ 590-650
Shale, black, soft_____________________ 650-710
Limestone, brown_____________________________ 710-800
Limestone, gray______________________________ 800-890
Limestone, gray-brown, very dense._______________ 890-1, 470
Limestone, sandy, gray and white_________________ 1, 470-1, 575
Sandstone, white; small yield of salt water_________ 1, 575-1, 580
Sandstone and blue shale, alternating layers about
6 feet thick___.____________________ 1, 580-1, 650
Limestone, gray; salt water at bottom_____________ 1, 650-1, 700
Limestone, gray, brown__________________________ 1, 700-1, 800
Limestone, brown, very hard; salt water at 1,940 feet_ 1, 800-2, 000
MONTGOMEBY COUNTY
[Area, 516 square miles. Population, 30,882]
GENERAL FEATURES
Montgomery County, which occupies the north-central part of
the region described in this report (pi. 1), lies on the most fertile and
thickly populated part of the Highland Rim plateau. The county
seat, Clarksville (population 9,242) is the principal commercial center
of this upland area. Most of the county is a slightly rolling plain
comprising extensive flat tracts of the Highland Rim peneplain (pp.
16-18) and shallow mature drains, which are presumably adjusted to
the Nashville Basin stage of planation (pp. 20-22). Many parts of
the peneplain remnants, especially in the northeast quadrant of the
county, drain into sink holes in the limestone or into small intermittent
and perennial ponds at the bottom of shallow undrained depressions.
These ponds occur at all altitudes and most of them are far above the
general level of the ground water. Some are probably caused by the
filling of sink holes or natural wells by impermeable debris; others
are probably due merely to unequal depth of chemical weathering of the
limestone. The peneplain remnants range from about 575 to 700 feet