526 Taylor. — Endemism in the Bahama Flora . 
subsidence and emergence is unquestioned. Separating this group from 
those of the Great Bahama Bank, however, there is a passage of over five 
thousand feet depth. All the islands on the Great Bahama Bank are only 
just above the surface, the bank itself having scarcely 20 feet of water over 
it, so that they have been connected among themselves at some period of 
their history. All of the islands scattered to the southward of the Great 
Bahama Bank (group c ) are surrounded by such depths of water that from 
it and from one another they must have been separated no matter what the 
local fluctuations of level throughout the archipelago may have been. 
Evidence collected by Alexander Agassiz and more recently by the 
Geographical Society of Baltimore puts the extreme changes of level 
throughout the islands as not over 200 feet. The oceanic depths between 
the Little Bahama and Great Bahama Banks and scattered islands to the 
southward are so great that no dry land connexion between them could 
have been possible. The authors of * The Bahama Flora ’ say in the 
introduction to it, ; There is no evidence that there ever was land connexion 
with either Florida, Cuba, or Hispaniola’ [Haiti], a statement abundantly 
justified by ocean depths often in excess of twelve hundred feet and not 
infrequently of over ten thousand feet. 
The amount of emergence and subsidence of the islands is pretty 
accurately known, especially from the study of the ocean holes on the 
banks. The depths of even the shallowest of these indicate that at some 
period in the past, and not so very long ago, the archipelago must have 
risen so far out of the water that the Bahamas must then have consisted 
of one large island to the north, the Little Bahama Bank of to-day, another 
and much larger island to the south, the Great Bahama Bank, and a group 
of isolated islands to the southward, never connected with either of these 
large land masses, nor with each other. The largest of the group is Inagua. 
The present Bahamas consist of wind and sea borne material piled up 
at the time of this emergence, all the area within the dotted lines on the 
map having since been covered by the sea, except for the islands exposed 
at present, the 661 cays, and thousands of rocks, almost awash, that make 
navigation so perilous. 
\b) Origin of Endemics . 
With only a single endemic genus, all the rest of the endemic species 
are in genera that are found either on the Florida mainland, the larger 
West Indies to the southward, or in many cases from more remote 
regions. 
Of the 76 genera in which all the Bahama endemics are found, except 
the endemic genus Neobracea ) 47, or 63 per cent., are genera mostly 
containing numerous species of rather wide distribution. Nineteen, or 
25 per cent., are genera found only in the West Indies or adjacent South 
