376 TRANSACTIONS OF THE CANADIAN INSTITUTE. (Vou. VIII 
It appears certain, therefore, that the ancient distribution of land 
including (1) the free waterway between the Caribean Sea and the 
Pacific Ocean ; and (2) the Atlantis Land, was not specially tertiary, but 
came to an end in the tertiary period, having probably endured since the 
jurasic period, though it is probable that the limits of Jules Marcou’s 
hypothetical jurasic continent (Marcou, Roches du Jura, 1860), should 
not have included Central America, which, with the Caribean Sea, were 
probably under water at that time, whilst the land extended from the 
East of the Antilles to North Africa. (See Journ. Geol. Soc., Lond., 
Vol. XXII, 1866, page 589, and Geol. Mag., Lond., 1867, page 497). 
What further evidence may be derived from the invertebrate fossils 
of Trinidad and Jamaica will be briefly indicated in the succeeding 
portion of this paper. The evidence drawn from the distribution of 
vertebrate animals seems to have lent some further and very important 
light to the discussion of the subject, as just noticed in the case of the 
egyptian fossil vertebrates. But the distribution of living reptiles has 
enabled Hans Gadow to furnish a nearer approximation to the probable 
arrangement of Central-American land than any yet presented 
According to his diagrams (Proc. Zool. Soc., Lond., 1905, II., page 235) 
Central America and Panama were under water until the end of the 
eocene period and rose into land during the miocene, being then united 
to Cuba, Haiti and Jamaica. The latter islands had been partly or 
wholly submerged until that time. They doubtless formed part of the 
margins of the Atlantic Land, which is thus shown to have lain to the 
eastward and northward of the Caribean Sea. 
The work of Messrs. Jukes-Browne and Harrison on Barbados was 
a notable addition to our knowledge of the geology of the West Indies, 
and especially of the oceanic deposits. Speaking of the latter they say : 
“ Radiolarian ooze does not exist in the Atlantic, but is found in the 
Pacific and Indian Oceans at depths of from 2,000 to 3,000 fathoms. 
Its existence in Barbados, therefore, suggests the idea that it was formed 
in a deep basin, which was open to the Pacific . . . . and consequently 
at a time when the Isthmus of Panama did not exist.” (Report on 
Geology of Barbados, 1890, and Journ. Geol. Soc., Lond., 1892, page 
224.) 
Gregory (in the Journal of the Geological Society of London, 1895, 
page 296 and seq.) has contributed some very pertinent observations 
towards the solution of the question. I propose in some respects to 
follow his method in this paper, that is to say, I shall deal with some 
