ANCIENT ANTILLEAN CONTINENT 
293 
emerged at the beginning of the Tertiary Era, and must then 
have been joined by land with Mexico. Some time during 
the Oligocene Period Professor Schuchert again records a 
complete submergence of all the West Indian islands except 
the Bahamas. But such ancient types as Typhlops, Soleno- 
don and many others, could not have been destroyed. We 
might suppose that they took refuge on the Bahamas, and 
thus repopulated the other islands subsequently. Such a 
theory, however, is exceedingly unlikely. A much more pro¬ 
bable explanation is that the Antilles were reduced to small 
islands, and retained their old animals and plants. In early 
Miocene times all the Greater Antilles were certainly raised 
above the sea, and must have been then connected with one 
another. Jamaica was joined to Guatemala, and Cuba to 
Mexico, but Jamaica must have separated early from Haiti. 
While the islands were joined to one another, an interming¬ 
ling of the more active ancient types occurred, the less pro¬ 
gressive ones being forced to the higher altitudes by the new 
arrivals from Mexico and Central America. During the whole 
of Miocene times Yucatan was apparently below sea-level. 
When it rose in the Pliocene Period, it may have had a short 
land connection with the Antilles by way of western Cuba. 
An opportunity was then afforded the mammals of South 
American type like Amblyrhiza, Megalocnus, and others to 
spread to the islands. The smaller West Indian mammals 
came earlier. Central America, during the existence of this 
Yucatan land bridge, may still have been separated from 
North and South America. At this time the Lesser Antilles 
probably had an independent land connection with Venezuela ; 
but that there was an Antillean Continent connected with the 
mainland in Pleistocene times, as suggested by Dr. Spencer, 
when Central America had already been invaded by the North 
and South American immigrants, is entirely opposed to the 
results derived from a study of the fauna and flora. 
As for the trans-Atlantic land bridge, we cannot assume 
that it oscillated up and down like the Antillean area, where 
peculiar local conditions produced exceptional changes of land 
and water. Some time during the Eocene Period it must 
have enabled European types to travel right across the 
Antilles and whatever portions of Central America then 
