E. A. Smith— Geology of Florida. 295 
Southern Coast of Florida.” The author describes the lime- 
stone of the Keys—in whicb the fossils are all identical with 
the shells living in the surrounding waters—and points out the 
agency of the Mangrove tree in the formation of islands be- 
tween the mainland and the Keys. At Tampa Bay he con- 
firms the observation of Conrad respecting the Tertiary age of 
Saag there, which he says extends doubtless to Charlotte 
arbor. 
The limestone which underlies the Everglades he states to 
be similar in every respect to that at the mouth of the Miami 
River, whieh, in turn, is of the same age as the rocks examined 
at Key West and elsewhere inside the reef. He calls attention 
to the fact that an elevation of the Keys, of about ten to 
twenty feet, would form a ridge similar to that surrounding the 
ters of flint, as occurring in the white Orbitulite limestone 
Which is common throughout the portion of Florida between 
Tampa and Pilatka. The flint was collected about forty miles 
West of Pilatka, and upon examination of thin sections by the 
Microscope, Orbitulina, Nummulina, Rotalia, Teaxtilaria, etc., 
Were recognized in numerous specimens. 
Tn a letter to Professor Dana, Dr. W. I. Burnett (this Jour- 
hal, II, vol. xvii, p. 407) calls attention to the circumstance 
that the peninsula of Florida is by no means so flat as is gen- 
rally supposed, for surveys made by Gen. Barnard establish 
the fact that there is an elevated ridge in places 2374 feet 
