OCKLOCKNEE AND AUCILLA RIVERS. 
105 
The materials seen in this exposure are characteristic of those of 
the northern part of Leon and Jefferson counties. Cross-bedding 
in the sands is frequently observed. White partings between the 
layers of sand is common to the area. A band or stratum of green¬ 
ish clay such as that seen in this section is of very general occur¬ 
rence. The laminated appearance sometimes seen in these deposits 
is shown in the photograph of plate 6, which represents a cut in 
the public road a mile north of Thomas City, in Jefferson County. 
On the Ocklocknee River occasional exposures of this formation 
may be seen from the. crossing of the Seaboard Air Line Railway 
for about 15 miles down stream. One of the good exposures is that 
found at Jackson Bluff. This formation is shown also on many 
of the small streams tributary to the Ocklocknee River. The mill 
site on Freeman Creek at the. crossing of the Jackson Bluff road 
rests on the greenish sands of this formation. The fuller-s earth 
horizon has been detected on a small stream entering the Ocklock¬ 
nee River on property belonging to the Allen estate. This is prob¬ 
ably near the north side of section 36, R. 3 W., T. 1 S. 
Other exposures of deposits which are tentatively referred to 
this formation are seen in all road cuts in north Leon and Jefferson 
counties, although usually much altered in the shallow cuts by disin¬ 
tegration. Upon being affected by the processes of decay the 
materials of this formation undergo well marked and characteristic 
changes. The clay-producing minerals partly disintegrate; the 
small constituent of iron becomes oxidized and stains the formation 
red. Another early effect of decay is the obliteration of the strati¬ 
fication lines giving the formation the massive appearance seen in 
all shallow cuts. In an early stage of decay the material becomes 
mottled and blotched, being iron-stained in streaks and patches 
where surface waters have permeated. Where more completely 
decayed and more thoroughly permeated by surface waters, the 
material becomes uniformly red, and is usually more or less loamy 
in character, and thus passes into soil. 
STRUCTURE. 
The Alum Bluff formation, so far as is known, is conformable 
with the Chattahoochee formation and may therefore be expected to 
have the same structure. As in the case of the. Chattahoochee lime¬ 
stone, the formation probably has a slow dip to the south. This is 
indicated by the fact that on the Ocklocknee River the formation 
