SECOND ANNUAL REPORT—STRATIGRAPHIC GEOLOGY. 
107 
the use of such terms as '‘newer,” “cold water,” or “Chesapeake” Mio¬ 
cene. As early as 1897 1 paleontologic studies determined the proper 
correlation for the rocks of Oligocene age, and thus left in the Mio¬ 
cene that portion which was formerly known as “new” or “Chesa¬ 
peake” Miocene. This usage is in accordance with the later papers 
of Dali. 2 
To the beds of true Miocene age Dali 3 gave the name “Chesapeake 
group.” This name was originally proposed by Darton 4 for the Neo¬ 
cene beds of Maryland and Virginia bordering on Chesapeake Bay 
and belonging to Dana’s Yorktown epoch. Chesapeake as used by 
Darton is the name of a formation, but it was subsequently used by 
Dali to include a number of beds which he designated the Chesapeake 
group. “The term Chesapeake group, as independently suggested, 
here includes as typical Darton’s Chesapeake formation and also all 
other beds belonging to the same horizon and containing the same 
general fauna on the Atlantic and Gulf coasts of the United States.” 5 6 
In accordance with the usage proposed by Dali, the name Chesapeake 
is a general term to include all of the Miocene of the Coastal Plain. 
In 1892, Dall G divided the “Chesapeake” of Florida into two for¬ 
mations, which he called Jacksonville limestone and Bcphora bed. In 
a subsequent paper by the same author these two divisions are placed 
together. “After the elimination of the Oligocene series from the so- 
called Miocene of Florida, we have remaining practically only one 
series of beds, which have been identified over a considerable area of 
northern Florida. The Miocene appears as a soft limestone rock in 
the vicinity of Jacksonville, and has been traced by material from 
artesian wells on the east side of the peninsula as far south as Lake 
Worth. The layers of fossiliferous marl in the vicinity of the Chipola 
River, at Alum Blufif, and other localities in Western Florida are 
usually less than thirty feet in thickness, but counting unfossiliferous 
clays, etc., it has been estimated that the rocks of this age in Florida 
may have attained to a thickness of some five hundred feet or less.” 7 
1 Dali, Wm. H., Descriptions of Tertiary fossils from the Antillean region. 
U. S. Nat. Mus. Proc., vol. xix, No. 1110, 1896, p. 303. 
2 Eighteenth Ann. Rept., U. S. Geol. Survey, p. 329, 1896-97. The Floridian 
Miocene, Trans. Wagner Free Inst., 1886-1903, p. 1594. 
3 Dali, Wm. IT., and Harris, G. D. Neocene of North America. U. S. Geol. 
Survey, Bull. 84, 1892, p. 122. 
4 Darton, N. H., Mesozoic and Cenozoic formation of eastern Maryland and 
Virginia. Geol. Soc. Amer. Bull. 2, pp. 443-445. 
5 Dali, Wm. H., Neocene of North America. U. S. Geol. Survey, Bull. 84, 
1892, p. 123. . 
6 Dali, Wm. H., Neocene of North America, U. S. Geol. Survey, Bull. 84, 
1892, p. 124. 
7 Dali, Wm. H., The Tertiary Faunas of Florida, Wagner Free Inst., Trans., 
vol. iii, part 6, 1893, p. 1594. 
