GEOLOGIC SECTIONS ACROSS THE EVERGLADES. 73 
Heilprin to the post-Pliocene*. Of the fossils Heilprin says “All 
the molluscan forms occuring in the limestone are indentical with 
the species now living in the river”. Dali writing is 1887 agrees 
with Heilprin in referring the limestone to the Quarternary,f but 
in a subsequent paper ff expresses the view that this is Pliocene, 
stating that the Planorbis rock “contains only extinct species or 
recent species also common to the Pliocene marl.” The shell marl* 
above the Planorbis rock was, however, still referred by Dali to 
the Quaternary. Dali has not given a list of the fossils on which 
the reference of these beds to the Pliocene is based, the few forms 
mentioned by him, including Planorbis Physa and Chione cancellata, 
are either long range forms, or being" only generically determined, 
lack stratigraphic value. By far the most abrupt break in this 
section both in lithology and in fauna is that occuring at the un¬ 
conformity that has been described which clearly marks the top 
surface of the Caloosahatchee marl, and unless the fossils above 
the unconformity are shown conclusively to be Pliocene, it is 
natural to assume that this stratigraphic break marks the dividing 
line in this section between the gliocene and the Pleistocene. 
COFFEE MILL HAMMOCK MARL. 
Lying upon the fresh water limestone, No. 3 of the preceding 
section, is a shell marl, the maximum observed thickness of which 
is about two feet. Although removed by erosion at the rapids this 
marl is very persistent. It is seen in place at Goodno’s Landing, 
Fort Thompson, and at Coffee Mill Hammock, twelve miles above 
Labelle. The predominating fossil is Chione cancellata , shells of 
which have been thrown out in great profusion by the dredge. 
j 
LAKE FLIRT MARL. 
The Coffee Mill Hammock shell marl is succeeded by a marl 
which is strickingly different both in lithologic appearance and in 
the fossils which it contains. The marl consists of a calcareous 
*L. C. p. 32 
fAmer. Jour. Sci. (3) Vol. 34, p. 169, 1887. 
ffU. S. Geol. Sur. Bull. 84, p. 144, 1892. 
x 
