SECOND ANNUAL REPORT—STRATIGRAPHIC GEOEOGY. 
81 
can scarcely be freed from the matrix. In one portion of the limestone horizon, 
the lower 25 feet, very large oyster shells are abundant. These weather out in 
good condition, probably because their matrix is argillaceous or because the 
limestone is softer. The greater portion of the limestone is hard and rings 
under blows of the hammer. 
No fossils were found in the basal argillaceous layers. These lower layers 
would, according to the literature, probably be referred to the Vicksburg. The 
limestone belongs to the Chattahoochee. The lithologic specimen of it was taken 
from the top of the exposure and a fair number of fossils were collected. The 
exposure was also photographed. This section was measured by a hand-level. 
The following descriptions were also furnished by Vaughan: 
Section , Aspalaga Landing. Thickness. 
Feet. Inches. 
5. Sand . .. 27 6 
4. White' lime rock. The surface appearance and color are those 
of chalk. This rock is indurated in thick, massive ledges 
and fragments show concentric exfoliation. Its color is 
originally bluish and becomes white upon drying. 39 6 
3. Chalky limestone more calcareous in the basal portion.18-20 
2. Friable limestone containing patches of blue clay and very 
poor remains of fossil mollusks. 1 4 
1 . Whitish tinged yellowish chalk which when kneaded in the 
water forms a whitish sticky paste. The stratum is 
sufficiently indurated to form a ledge and extends at least 
1 foot below the surface of the water. Thickness. 7 8 
The argillaceous basal portion of stratum No. 3 is about 2 feet, then fol¬ 
lows a chalky stratum and bluish clays at the base of No. 4. 
At the extreme upper end of the bluff the exposure is more satisfactory. 
The bluff face (Nos. 1 , 2, and 3, and the lower 10 feet, 8 inches of No. 4, total 
thickness 30 feet 5 inches) is white chalk with layers of more or less friable 
and argillaceous marl. Fossils are very numerous and several layers of the 
chalk especially in stratum No. 2 and at the top of the bluff face, but all are 
miserably preserved, there being no shell substance left, only casts. Nucula, 
Pecten, Venericardia, Lucina, Isocardia, Meretrix, Turritella, Stylophora solitary 
corals, etc., were observed. 
A resume of the exposure at Aspalaga excluding the surface sands, is as 
follows: 
Feet. Inches. 
4, . 39 6 
- 3, .. 11 
2, . 1 4 
1, . 7 8 
Total thickness . 59 6 
(Or roughly, 60 feet.) 
The whole of these 60 feet (perhaps excepting some marl beds near the 
top) is chalky limestone. This section was measured with a hand-level. 
I could not find the marl bed described by Dali and think it must have been 
simply a disintegrated chalky stratum or weathered chalk as the weathered chalk 
is frequently a clay marl. The limestone was sectioned at two places, one near 
