VERTEBRATES FROM MIOCENE, PLIOCENE AND PLEISTOCENE. 93 
formation, although containing comparatively few fossils, is re¬ 
ferred on the authority of Dali to the Miocene* *. 
The marine Pliocene deposits are also well developed in Florida 
and contain an abundant invertebrate fauna. The first recognized 
and best' known of these marine Pliocene deposits is the Caloosa- 
hatchee marl, well exposed on the Caloosahatchee River, as well as 
on some of the other streams of Southern Florida. More recently 
marine Pliocene marls in Eastern Florida have been described and 
designated as the Nashua marl*. 
In addition to these marine Pliocene and Miocene deposits, two 
other formations are found in Florida, which are believed to be 
approximately contemporaneous in age. These are the Alachua and 
Bone Valley formations, both of which contain vertebrate fossils. 
Of these the Alachua formation is the better known in literature 
and has usually been referred to the Upper Miocene or the Lower 
Pliocene. Upon the basis of vertebrate fossils the writer is inclined 
to refer both the Alachua and the Bone Valley formations to the 
Pliocene. 
THE ALACHUA FORMATION. 
The Alachua formation as here used includes the “Alachua 
clays” of Dali, with which is combined the “Dunnellon formation ’ 
of the writer. 
The term “Alachua clays’’ was proposed by Dr. W. H. Dali in 
1885 for the clay beds in the vicinity of Archer from which at that 
time extensive collections of vertebrate fossils were being made. 
The first published account in which this term was used, however, 
is found in Bulletin 84 of the United States Geological Survey, page 
127, 1892. The clays are there described as occurring in sinks, 
gullies and other depressions, and are considered by Dali as repre¬ 
senting a remnant of a previously more extensive formation. 
The term “Dunnellon formation” was first used by the writer 
in 1910 to designate the extensive deposits which hold the hard rock 
phosphates of Florida. While the prevailing phase of the Dunnel¬ 
lon formation is light gray phosphatic sands, the deposits include 
also local beds, lenses, or masses of clay, as well as phosphate rock, 
flint boulders, pebble conglomerate and limestone fragments. As 
the study of the Dunnellon formation progressed it became appar¬ 
ent that the vertebrate fauna of these deposits was essentially the 
* Fla. State Geol. Sur. Second Ann. Rpt. p. 128, 1909. 
* Wag. Free Inst. Sci. Trans. Vol. 3, pt. 6, p. 1594, 1903. 
