SECOND ANNUAL REPORT—STRATIGRAPHIC GEOLOGY. 
In 1892 Dali 1 called this formation “Ocheesee beds,” but in a 
subsequent paper he notes the absence of exposures at Ocheesee 2 and 
uses the names Chattahoochee formation 3 and Chattahoochee lime¬ 
stone. 4 As the formation contains considerable marl, the use of Chat¬ 
tahoochee limestone is not entirely satisfactory, and hence the name 
Chattahoochee formation is retained. 
Stratigraphic Position:—The Chattahoochee formation is known 
to rest unconformably on the underlying limestone of the Vicksburg 
group in southern Georgia. The evidence upon which this uncon¬ 
formity exists was summarized by Pumpelly in 1893. 3 According to 
this writer, there is usually a limestone conglomerate at the base of 
the Chattahoochee formation in southwestern Georgia, and the alti¬ 
tude of the contact between the two limestones varies considerably 
within short distances. The variations in altitude given by Pumpelly 
might, if considered alone, be regarded as due to deformation rather 
than to an erosional unconformity, but the evidence of erosion is 
strongly supported by the conglomerate which in some places resem¬ 
bles breccia, but in other localities contains rounded pebbles of the 
underlying rock. The difference in lithologic character between the 
limestones of the Vicksburg group and the Chattahoochee limestones 
is so marked that it would hardly be possible to mistake the source of 
these pebbles. The argument in favOr of the inequalities of the sur¬ 
face of the limestones of the Vicksburg group being due to erosion 
is strengthened by the paleontologic evidence. On evidence furnished 
by Poerste, Pumpelly states that the Chattahoochee at Griffins Creek 
contains a fauna characteristic of the upper part of the Vicksburg 
group, while the other localities examined contain faunas belonging 
to the lower part of that group. It thus appears that at Griffins Creek 
the deposition did not begin until after the formation of the beds 
exposed in the immediate neighborhood, or, in other words, that an 
island consisting of the underlying limestones of the Vicksburg group 
was not submerged until after the deposition of the lower part of the 
Chattahoochee formation. 
Tuomey also collected corals at the contact between the Chatta¬ 
hoochee and the underlying limestones, and Dr. Dali identified these 
1 Dali, Wm. H., Neocene of North America, U. S. Geol. Surv. Bull. 84, 1892, 
pp. 105-107. 
2 Dali, Wm. H., and Stanley-Brown, Joseph, Cenezoic Geology along the 
Apalachicola River, Geol. Soc. Am., vol. v, p. 154, 1894. 
3 Ibid, p. 152. 
4 Ibid, p. 155. 
° Pumpelly, Raphael. An apparent time break between the Eocene, and 
Chattahoochee Miocene in southwestern Georgia. Am. Jour. Sci., 3rd ser., vol. 
xlvi, 1893, pp. 445-448. 
