SECOND ANNUAL REPORT—STRATIGRAPHIC GEOLOGY. 
51 
was known as the “Vicksburg limestone .” 1 This name 2 had been used 
to include all the older Tertiary rocks of the peninsula, comprising 
both the Vicksburg and the deposits here called Apalachicola group; 
but with the increased knowledge of the geology of the State it was 
gradually restricted to the older limestones. Subsequent study in¬ 
dicated that this group of older limestones, while presenting but slight 
lithologic variation, was divisible upon paleontologic grounds into 
two parts, the lower division (here called “Peninsular”) being desig¬ 
nated the Vicksburg “limestone” and the upper division being named 
the Ocala limestone. Still later, Dali 3 proposed the abandonment of 
the name Vicksburg as applied to limestones of the peninsula of 
Florida, and the substitution of the term “Peninsular” for the lower 
division above described. He states: 
From the observations on the typical Vicksburgian by Coloney Casey it 
seems probable that the Orbitoidal limestone which forms the mass of the Flor¬ 
idian plateau, and which has been, in this work and in the literature generally 
called the Vicksburg limestone, may really form a different horizon altogether 
from the typical Vicksburgian and be intermediate between the latter and the 
nummulitic Ocala limestone. In order to promote clearness and avoid confusion, 
it is probably advisable to adopt a distinct name for the Orbitoidal phase or 
formation, for which I would suggest the term Peninsular limestone. This is 
intended, not as a permanent formation-name, but as a general term for the 
fundamental plateau limestone of Florida, in which a close and thorough study 
may result in the discrimination of more than one horizon or zone. 
The reason for the change suggested by Dali 4 is the fact that the 
fossils which have long been regarded as characteristic of the Vicks¬ 
burg have been found to occur in other horizons, and hence their 
occurrence in the limestones which underlie the nummulitic rock of 
the peninsula cannot 'be regarded as proof of equivalence of that lime¬ 
stone with the limestone at the type locality at Vicksburg, Miss. The 
question of the correlation of the Florida formations has been further 
complicated by the fact that there are two horizons represented in the 
bluff at Vicksburg. To avoid further confusion, however, the 
Oligocene rocks in Florida which were originally known as the Vicks¬ 
burg “limestone” are here designated the Vicksburg group. They are 
thought to comprise three formations, here called the Ocala lime¬ 
stone, the “Peninsular” limestone and the Marianna limestone. 
The “Peninsular” and Ocala limestones have already been recog¬ 
nized by Dali. The name Marianna limestone is here given to the 
soft, porous, light-gray to white limesiones of western Florida, which 
1 Dali, Wm. H. Neocene of North America, U. S. Geol. Survey, Bull. 84, 
1893, pp. 101-104. 
2 Smith, E. A. On the Geology of Florida, Am. Jour. Sci., 3rd ser., vol. xxi, 
1881, pp. 292-309. 
3 Wagner Free Inst, of Sci., vol. iii, pt. 6, p. 1554. 
4 Loc. Cit. 
