1908-9. ] THE GEOLOGICAL CONNEXIONS OF THE CARIBEAN REGION. 379 
and the latter lying near the islands off the coast of Venezuela as 
indicated in the map. The soundings to the west of the line of the 
Antilles show a rapid descent into deep water, and so do those to the 
north of the “continental shelf” to the north of South America. 
In my paper on the “Growth of Trinidad,” I have indicated the 
principal dislocations which occur in this locality; and there is no 
difficulty ininferring from this the existence of similar disruptions on 
the neighboring continent. The lines of dislocation are seldom simple, 
but consist of several sub-parallel or radiating fissures especially 
developed at certain points, such as the Gulf of Paria, which points may 
be considered foci of disturbances. For instance, another line of depres- 
sion appears to pass along the course of the Guarapiche River to the 
south of the Bergantin in the east of Venezuela, and this comes out on 
the coast between Nueva Barcelona and Unare. The upheaval of 
the southern part of Trinidad and the dislocations which separated that 
island from the South American Continent were certainly post-miocene ; 
but they may have been in progress during a very long period of 
geological time. In the paper referred to I have shown that in cretaceous 
times the greater part of what is now Trinidad was sea, the northern 
ridge alone rising above the water ; and that northern ridge itself was 
previously under water, being formed of materials probably derived from 
the north-eastward, while the materials of the southern part of the 
island were derived from the south-westward. Two conclusions seem 
to follow from this. First, that if such changes can occur on a compara- 
tively small scale, as in this case, there is no impossibility about their 
occurring on alarger scale. And, second, that as there was land to the 
north-east of Trinidad at e very ancient date (precretaceous or jurasic 
at the least) while all to the south and south-west was then sea, it is 
probable that the Atlantis was a very ancient land which gradually 
dwindled away through all the later mesozoic periods down to and 
including part of the tertiaries. 
In my paper on the “Growth of Trinidad” just referred to, I men- 
tioned the fact that during the cretaceous and tertiary periods the whole 
of the area now drained by the Orinoco and the Amazons was sea. It 
is quite probable that this sea communicated with the Pacific by means 
of a strait or channel of which the Gulf of Guayaquil is a vestige. In 
our present inquiry the existence of the Unare Hiatus on the northern 
coast of Venezuela is of some importance, as it was probably through 
that strait that the Caribean Sea communicated with the sea that filled 
the Orinoco Valley and covered the southern part of Trinidad. Could 
