186 
ORIGIN OF LIFE IN AMERICA 
that during early Tertiary times Antillean species were carried 
even as far as New Jersey. At no succeeding Epoch, says Dr. 
Dali, do we find such tropical and semi-tropical mollusks 
extending northward to such a distance from their present 
range. All these Tertiary deposits cease north of the Hudson 
estuary, and I have shown in a previous chapter (p. 41) 
that in later Tertiary times, at any rate, the coasts of New 
Yoi'k, Massachusetts and Maine extended far out into the 
present Atlantic. The hypothesis of the latter land extension 
having once joined Bermuda and the Bahamas, etc., seems to 
me supported by a variety of circumstances which I shall 
allude to later on. This would have excluded the Atlantic 
Ocean either partially or wholly from the Gulf of Mexico and 
the southern Atlantic States. Some time during the Miocene 
Period, or earlier, a sudden influx of northern species into the 
area hitherto occupied by southern forms occurred. Dr. Dali 
and Mr. Harris * endeavoured to account for this phenomenon 
by the supposition that the course of the Gulf Stream was 
gradually turned more off shore than it was before or is at 
present. 
If we assume, however, that a belt of land such as above 
described had hitherto existed, the gradual breaking down of 
its northern portion might have admitted the Atlantic waters 
into the sea which covered the southern States and have 
brought with it the new fauna, which had meanwhile deve¬ 
loped in the northern Atlantic Ocean (see Figs. 14 and 16). 
For a time these northern, cooler inshore waters were even 
able to penetrate into the Gulf of Mexico. Even if we grant 
the correctness of Messrs. Dali and Harris’s supposition of the 
altered course of the Gulf Stream, the cause of this deflection 
is more likely to have been produced by a change in the con¬ 
figuration of the northern land-masses than by that of Florida. 
Let us now study the flora and fauna of Bermuda, and 
endeavour to ascertain whether it supports in any way the 
theory I have advocated.f It is quite evident that the existing 
flora of Bermuda is only a remnant of the original one, before 
the early settlers, accompanied by hogs and rats, played havoc 
* Dali, W. H., and G. D. Harris, “Correlation Papers,” pp. 185—187. 
t Ileilprin, A., “ The Bermuda Islands.” 
