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1894.] Geology and Paleontology. 883 
accumulation of the Matanzas limestones (of Spencer), but in amount 
not exceeding a depression of from 100 to 1300 feet below the present 
level. There was a late Miocene mammalian fauna on the continent, 
but it did not extend into the Pliocene period, for no mammals of that 
date are known east of the Mississippi River. As the fauna flourished 
when the continent was at about the same altitude as now, the great 
change in elevation, causing the subtropical climate to become subare- 
tic, may have been sufficient reason for the restriction of the earlier 
life, whose descendants would have been extinguished by the drowning 
of the now insular region and 250,000 square miles of the continent. 
Again the continent rose to an altitude about as great as that of the 
Pliocene days, when it suffered an enormous erosion. During this ear- 
lier portion of the Pleistocene period, there was a rich mammalian 
fauna of horses, elephants, tapirs, camels, ete., but these were exter- 
minated by the succeeding depression which carried down the Antil- 
lean lands to the proportions of small insular masses, and reduced the 
plains of the northern continent by 150,000 square miles. Since that 
time there have been reélevations and minor undulations, but no con- 
nection between the islands and the continent, so that the modern 
types of mammals have been unable to reach the West Indies. 
The changes which have occurred in the West Indies and those of 
the adjacent portion of the continent have been nearly identical, but 
the movements in the Antillies appear to have been somewhat more ener- 
getic, and the geographical evolution of the continent is best studied 
from the West Indian phenomena, but neither region is complete with- 
out the other. The general problem could not have been elucidated 
until the investigations which I have made upon the fjords. 
The connection of the Antillean waters with the Atlantic and the 
separation from the Pacific Ocean should be noticed. There was free 
communication between the two oceans about the close of the Miocene 
riod. The Pliocene union of the two continents separated the two 
oceans, although there may have been an enclosed sea between Cuba 
and Jamaica. With the subsidence of the land at the close of the 
Pliocene period, there was only a narrow and shallow communication, 
between the Antillean waters and the Pacific, but the connection with 
the Atlantic was more complete than now. These connections were 
again closed during the Plistocene elevation. With the depression of 
mid-Plistocene days, the Atlantic was again admitted to the Mediter- 
ranean Seas, and it is also probable that there were two or three shal- 
low passages leading to the Pacific. During the later Plistocene and 
modern days there have been no change of level which have effected 
