(no The American Geologist. December,. 1803 
erature oT earlier reports of surveys by the several states and by the 
national government, and prepared the sixth chapter, on the freshwater 
Neocene deposits of the interior region of the United States, and the 
concluding seventh chapter, which is an annotated list of the names (ex- 
ceeding two hundred ) which have been applied to our Cenozoic beds 
and formations, with indications of the origin of the names and cita- 
tions of authors and dates. Dr. Dall has revised and correlated the 
data relating to the Neocene formations, mostly marine, which are ex- 
tensively developed along the coastal plain of the Atlantic and Gulf 
of Mexico and more narrowly and less continuously along the Pacific 
coast, and has written the chapters on Florida, British Columbia, and 
Alaska. To this work Dr. Dall brought his intimate knowledge of our 
Tertiary and recent molluscan faunas, and the fruits of his years of ob- 
servation in Alaska and Florida, for each of which exceptionally 
copious description and discussion are presented. 
Lyell's Miocene and Pliocene are united under the term Neocene, 
but the former terms are also much used throughout the work; and the 
relationship of the preceding Eocene strata and of the succeeding 
Pleistocene and recent formations leads in many portions, especially in 
treating of Florida, to the consideration of the entire Cenozoic system, 
extending through the Tertiary and Quaternary eras to the present 
time. The Miocene period in the eastern United States is defined as 
beginning with an uplift by which central Florida was first raised above 
the sea to form an island, and ending with a similar vertical movement 
which permanently united this island with the mainland to the north 
and west and probably also united North and South America. As thus 
defined, the Miocene comprises two epochs. During the first, typified 
by the Chipola beds, a warm-water marine fauna reached north to New 
Jersey, the conditions there resembling those now at the isthmus of 
Panama; and thesupposed Miocene leaf-beds of Greenland were per- 
haps synchronous. The second, or Newer Miocene epoch, to which the 
Ecphora bed and Chesapeake formation belong, was characterized by 
the extension of a relatively cold-water fauna southward to Florida and 
the Appalachicola river. 
The marine Pliocene, well developed in western Florida, and extend- 
ing thinly northward to South Carolina, and perhaps to southeastern 
Virginia, is marked by a return to the Florid ian region of a warmer, 
chiefly Antillean, invertebrate fauna; but many of the Chesapeake spe- 
cies survived the change and are still living on the northern shores 
of the gulf of Mexico. During the middle part of the Pliocene period 
Florida and even the interior of the continent were reached by a very 
remarkable immigration of South American terrestrial vertebrates, and 
others came into the Florida peninsula from the northern fauna. "The 
rhinoceros, the wild horse, the llama, the Columbian elephant, the mas- 
todon, the glyptodon, and various enormous tortoises wandered along 
the shores of the lakes and through the marshes, while the saber-toothed 
tiger lay in wait.'" Some of the great Pliocene mammals, as the masto 
don. continued their existence during the Glacial period, and it is found 
