214 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
the lands produced by this Mid-Tertiary revolution, it was certainly one 
of the most marked and important events in Antillean history, and pro- 
duced the major configuration of the islands and adjacent waters, which 
have persisted notwithstanding the modifications of later times. It is 
true that this configuration has suffered considerable alteration in subse- 
quent epochs, through degradation and oscillations of level, but it has 
remained as a major mass out of, upon, and around which all later 
events have been carved. ` 
'The next events in Antillean and Central American history were the 
degradation, partial subsidence of the West Indian region, and dismem- 
berment of this extended Mid-Tertiary Antillean land. The previously 
connected Antillean lands were severed and dismembered into almost 
their present outlines. The connections between the Antillean islands 
and the Bahaman and south Floridian lands were submerged ; the waters 
of the Gulf Stream now flowed over the latter. The Misterosa and 
Rosalind peninsulas were submerged, and the littoral of the Caribbean 
migrated southward and westward and impinged upon what are now the 
land margins of Nicaragua, Costa Rica, Panama, Colombia, and Vene- 
zuela. During this epoch it is also probable that Trinidad, Tobago, and 
the adjacent islands were severed from the South American coast, and 
the disconnection of Barbados from the South American continent still 
further accentuated. No record has as yet been discovered showing 
that the Windward Archipelago participated in this downward move- 
ment. On the contrary, the formations recording it were not deposited 
in Barbados, and the volcanic piles of the Caribbean were more extended 
than at present. 
The Andean, Central American, Mexican, and Windward voleanoes 
were as active as ever, piling up the vast eminences which from their 
superior magnitude have so obliterated the no less interesting minor 
topographie features. In this epoch ended, long before man had ap- 
peared upon the earth, all traces of Antillean land expansions upon 
which the least theory of an Atlantis could have been postulated, and 
all attempts at restoring connections between the islands, or the islands 
and the mainland, in subsequent epochs of late Tertiary and Pleistoceno 
time belong to the realms of fancy. 
The exact date of this late Tertiary dismemberment of the expanded 
Antillean lands cannot be stated with exactness. In my opinion, it was 
during late Miocene and Pliocene time, beginning with the Bowden 
epoch of the Jamaican sequence. Dr. Dall holds that the age of the 
Bowden beds is late Oligocene. It is my opinion that the stratigraphic 
