SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 93 
1 . Superficial sands . 8^2 feet. 
2 . Red clay . 2]/ 2 feet. 
3. Reddish and yellowish streaked sands .... 66 feet. 
4. Aluminous clay . 24 feet. 
5. Chesapeake gray marl . 35 feet. 
6 . Alum Bluff sands with streaks of clay. 21^2 feet. 
7. Hard Chipola marl to water (variable)............ 3*4 feet. 
Total thickness above water... 160^4 feet. 
The composition in detail of these several beds is as follows: 
Number 1—Pale yellowish gray incoherent sand. 
Number 2—Hard reddish clay weathering with vertical face. 
Number 3—Streaky yellowish and reddish sands with small little-worn 
gravel, of siliceous character, mixed with it. Near the lower third a few obscure 
impressions, possibly representing fossils, were observed by Stanley-Brown. 
The lower 3 feet of the sand is more or less loamy from admixture with under¬ 
lying clay. They are distinctly stratified in conformity with the other beds of 
the bluff. 
Number 4—Tough gray aluminous clay weathering nearly vertical with a 
few fragments of vegetable matter in it and some obscure indications of gastropod 
and bivalve fossils, the shells entirely dissolved and represented chiefly by color- 
marks in the clay. The appellation of “lignitic,” heretofore applied to this clay 
on the authority of Mr. Johnson, can not be regarded as justified, as the amount 
of phytogene material is trifling. The fossils may have been marine or fresh 
water. No satisfactory evidence is afforded by their faint traces, as observed 
by us. 
Number 5—Bluish gray tough clayey marl replete with characteristic 
Chesapeake fossils, especially Mactra congesta. The upper six inches is dis¬ 
colored by iron oxide, derived from the water oozing from the bed above, which 
has also dissolved the shells, leaving only cavities. Toward the north, at a point 
(C. of figure 2 1 ) near the camp the Chesapeake is thinned to 5 or 6 feet in 
thickness. ■ 
Numbers 6 and 7—The Chipola marl is compact and of a dark-reddish color 
from hydrated peroxide of iron contained in it. The fossils which are abundant 
are rather soft. Orthaulax is the most common shell; there are no traces of 
Orbitolites. The matrix is chiefly sand mixed with clay. At least 6 or 8 feet 
of the Chipola is below the water; it rises at the lowest stage of the river from 
3 to 11 feet above the water’s edge, weathering almost like a rock. There is no 
well defined line of separation between the marl and the Alum Bluff sands 
(number 6) above it, but the change takes place in a space of 5 feet, the lower 
portion of the sands containing more or less of the Chipola fauna. Above this 
they are mottled, bright ferruginous and yellow, and exhibit distinct marks of 
cross bedding. They contain sheets^laminae or lenticular streaks of clay—which 
show abundant leaf remains resembling willows and other water-loving plants, 
while the sands in the lower part of the bed contain large leaves and stalks of 
palmetto or other palm-like vegetation, the thicker parts of which are reduced to 
the condition of lignite. These are too friable to remove without previous 
hardening applied in situ. The upper part of these sands did not show any 
fossil remains at the points where we examined them. 
1 Not published in this report, see original paper. 
