OCKLOCKNEE AND AUCILLA RIVERS. 
107 
passes below water level, thus indicating a dip in excess of the 
gradient of the stream. Within the formation itself bedding lines 
can be followed to some extent, and when not disturbed either by dis¬ 
integration or by slumping the lines are found to be approximately 
horizontal with probably a slight south dip, scarcely perceptible in 
any one exposure and recognizable only when a given stratum is 
compared in successive exposures. 
One of the most easily recognizable divisions of the formation 
is a stratum of blue clay, which, although having a thickness of only 
about three feet, is very persistent over this area. This clay is 
seen in the following exposures in which the actual level of the clay 
has been determined: 
Bainbridge road, 4 miles north-west of Tallahassee_.170 ft. 
Meridian road, 5% miles north of Tallahassee_-_170 ft. 
Meridian road, 4 miles north of Tallahassee-164 ft. 
Thomasville road, 4 miles north-east of Tallahassee___ _i6i ft. 
Thomasville road, 7 miles north-east of Tallahassee_159 ft. 
St. Augustine road, near east city limits of Tallahassee_-_153 ft. 
Bellair road, about 1 mile south of Tallahassee-151 ft. 
St. Augustine road, 7V2 miles east of Tallahassee___147 ft. 
In recording the level of this clay it is necessary to make sure 
that the deposits are in place and that the elevation has not been low¬ 
ered either by subsidence due to underground solution, or by creep 
or slump down the slope of the hill. The clay stratum is a line of 
weakness in the deposit, and creeping and slumping frequently 
take place along this plane. Thus at the locality referred to on the 
Meridian road 5^2 miles north of Tallahassee, this clay stratum, 
although having a thickness probably of only about three feet, is 
seen in the exposure for a distance along the slope of the hill of 380 
feet, and through an apparent vertical interval of 22 feet. At many 
other localities, also, the clay has an apparent thickness on the slope 
of the hill which is obviously greater than its actual thickness. Sim¬ 
ilarly the overlying sands following the slope of the hill seem to 
have a far greater thickness than they actually have in vertical sec¬ 
tion. On a hill where the formations are known to be affected by 
slumping, only those strata which are undisturbed can be used in 
determining the thickness of the section or the level at which the 
stratum lies. 
On Little River in Gadsden County, west of Midway, a shell 
marl phase of the Alum Bluff formation is exposed at the public 
