The fresh-water and terrestrial mollusks of stratum No. 2 were submitted to Dr. Paul Bartsch, of the U. S. National Museum, who has reported on them (Rep. Florida Geol. Surv., vol. VIII, p. 144). He lists 29 species, all living.
The marine mollusks found in the stratum called No. 1, and which the writer refers to the first glacial stage, have been studied by Mr. W. C. Mansfield, of the U. S. Geological Survey (Rep. Florida Geol. Surv., vol. IX, pp. 78–80). Seventy-four species are specifically determined, and of these 61 are identical with living forms. Three or four species are possibly extinct. There is no question that the deposit belongs to the Pleistocene.
Nearly all of the plants were found in the bed designated as No. 3, the upper or muck-bed. These were studied by Dr. Edward W. Berry, of the Maryland Geological Survey. His report, published in 1917 (Rep. Florida Geol. Surv., vol. IX, pp. 19–33), states his conclusion that the plants belong to the late Pleistocene, either the Peorian or the Late Wisconsin. It may be stated that Dr. Berry adopts the theory that the terraces supposed to be found along the Atlantic Coast were formed during stages of submergence beneath the sea, the lowest one late in Pleistocene time.
Lee County.—The whole of Lee County is occupied by Pleistocene deposits which form a part of the Pensacola terrace. Naturally the Pleistocene is overlain, generally, at least, by accumulations of Recent materials, and it may not always be easy to distinguish the one from the other. So far as the writer knows, all the vertebrate fossils discovered in this county have been collected along Caloosahatchee River above Fort Myers. The geology of this river has been described by Heilprin (Trans. Wagner Inst., vol. I), Dall (Bull. 84, U. S. Geol. Surv., pp. 142–145), Matson and Sanford (Water Supply Paper 319, pp. 134–138), Sellards (2d Ann. Rep. Florida Geol. Surv., p. 123, 6th Ann. Rep. Florida Geol. Surv., pp. 41–46). The Pleistocene is underlain by Pliocene marls and hard and soft limestones and consists of beds of muck, marl, and sand of little thickness. At Labelle it is said (Sellards, 2d Ann. Rep., p. 126) that there is a fossiliferous Pleistocene marl covered by 3 feet of sandy loam. The following seem to be the species which have been found in the Pleistocene in this region:
- Elephas imperator (p. [163]).
- Equus leidyi (p. [199]).
- E. sp. indet. (p. [199]).
- Bison latifrons (p. [264]).
- Mylodon harlani (p. [40]).
- Testudo obtusa?.
- Trachemys bisornata.
- T. sculpta.
The presence of Elephas imperator is an indication that the deposits belong to the early part of the Pleistocene. None of the species appear to indicate an older stage than the Aftonian.
Dade County.—Sellards (8th Ann. Rep., p. 106) records that some fragmentary remains of a proboscidean had been found in Miami River, Dade County.
Palm Beach County.—On page 105 of the report just cited, Sellards stated that Elephas columbi (p. [160]), Mammut americanum (p. [123]), Equus complicatus (p. [200]), and Bison sp. indet. (p. [264]) had been found in the Palm Beach Canal, constructed to drain the Everglades.
At some unknown point in the Everglades, possibly in Lee County, there was found many years ago a tooth of an elephant which the writer believes belonged to Elephas imperator, already mentioned on page [163]. It was formerly reported as E. columbi.