DaU's Tertiary Fauna of Florida. — Schuchcrt. 151 
the fauna indicating a still warmer sea temperature inaugurated the Pli- 
ocene. During this period a continuance of immigration of suhtropical 
forms, IMiocene exiles and newcomers, is notable. These pushed their 
way northward, one species, at least, reaching Martha's Vineyard. The 
records of this extension were partly obliterated by the ice-sheet of the 
Glacial period and, even as far south as the Carolinas, arc very frag- 
mentary. The end of the Pliocene is the beginning of the Glacial epoch. 
The Pleistocene of Florida shows a change for the cooler and an elimi- 
nation of the most purely tropical forms from the fauna, but nothing 
like the clean sweep at the beginning of the Miocene. The latter is the 
sharpest and most emphatic faunal change since the Cretaceous on our 
coasts. With the exception of a few widely distributed and uncharacter- 
istic species the entire Molluscan fauna of the north shore of the Gulf 
was swept away and replaced by a more meagre fauna of a different type. 
In the face of this revolution no proposition to extend the limits of the 
Miocene farther down the column seems to me defensible. 
"The above summary of the changes in the period between the Vicks- 
burg and the Glacial epoch was sketched in all its main outlines in Bul- 
letin 84 of the United States Geological Survey in 1891, and amplified in 
the introductory remarks to my 'Table of Tertiary Horizons' in 1895. 
Subsequent study has only confirmed the views drawn from the earlier 
work, and, as a whole, the establishment of this general view may be re- 
garded as the most important result of this study of the Tertiary faunas 
of Florida. A thorough knowledge of the present faunas of the coast is 
almost essential to enable one to fully recognize the weight of the evi- 
dence, but I -am convinced that in its main features the above sketch will 
stand the test of time, even though some amelioration may be expected 
in minor details. 
"In some recent papers on the Oligocene and Eocene it has been 
suggested that the presence or absence of identical species in the Ter- 
tiary beds on either side of the Atlantic is an important factor in decid- 
ing the correlation of geological horizons. While this is partially true 
of older geological horizons, after the Mesozoic epoch the faunal charac- 
teristics of the shallow water Mollusca of diflferent regions became 
rapidly distinctive. Even in the Eocene but two or three: species can be 
claimed as identical on both shores of the Atlantic, and in later i)enods 
it would be most unreasonable to demand of subtropical marine inverte- 
brate faunas in widely separated regions that they shall offer a series 
of identical species on pain of being refused correlation. We cannot ask 
that they shall do more than present equivalent stages of evolution in 
relation to preceding and subsequent faunas, or that a no greater number 
of identical species shall be required than are found in the contemporan- 
eous faunas of the present day in similar cases. This is undoubtedly true 
of the faunas treated of in this Memoir." 
EXPLANATION OF TABLE I. 
"This table contains in the left hand column the names of the form- 
ations, preceded by a capital letter in descending order. There are nine- 
teen formations mentioned and the first nineteen columns to the right. 
