80 
FLORIDA STATE GEOLOGICAL SURVEY. 
total thickness of the Chattahoochee formation here ex¬ 
posed is 80 feet. 
1. Alluvium of river bottom composed of reddish sands along 
the river, thickness ... 20 
No exposure of beds beneath the river alluvium was seen. 
Total .... 120 
In commenting upon this section, Vaughan says: 
It is evident that I did not examine the specific locality described by Dali, 
for I did not see his Chattahoochee limestone. The upper part of his No. 2 
is the lower part of my No. 2. From Dali’s description the whole of my No. 2 
would be referable to the Alum Bluff. The combination of his section and mine 
gives a thickness of over 80 feet. His maximum thickness is 67 feet. 
The following more detailed* section by Vaughan shows the char¬ 
acter of the rocks exposed in the lower part of the section given 
above. 
Feet. Inches. 
3. White argillaceous chalk in harder and softer layers. 46 
2. Very calcareous blue clay. 2 
1. Indurated calcareous clay stained yellow in places..♦... 15 3 
Six feet 6 inches above the base is a fine-grained, very 
calcareous marl white or slightly tinged with yellow in 
spots. This stratum contains casts of many shells, etc. 
Total . 63 3 
At Wiley's Landing on the Chattahoochee River, about seven miles 
above River Junction, Vaughan obtained the section given below, but 
it has not been correlated with the other sections farther down the 
river. 
Section of bluff at Wiley’s Landing. 
Thickness. 
Feet. Inches. 
Red clay .5 or 6 
Limestone . 25 
Not definitely exposed, clay or limestone, probably limestone 
or calcareous clay . 5 
Limestone containing a large oyster, Isocardia, Venus, 
Pyrula, etc. 5 
Unexposed surface red clay, apparently underlain by lime¬ 
stone ..... 
Bluish sticky clay . 5 
From water’s edge to 5 feet 6 inches not definitely exposed, 
but apparently bluish sticky clay. There is much lime¬ 
stone detritus over the surface, it having rolled down 
from the upper part of the bluff. Thickness. 5 
11 
The surface of this bluff is so covered by red clay and talus from above 
(limestone pebbles and boulders) that it is not possible to discover the details 
of the section. The basal 11 feet are argillaceous while the succeeding 47 feet 
are for the most part limestone. But the rock is so indurated that the fossils 
