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Birds of the Cayman Islands. 
ridge extends from Cape Cruz, the most southerly point of 
Cuba, right across this western division of the Caribbean Sea 
into the Bay of Honduras. 
The major part of this ridge lies at a depth of 1000 
fathoms, but here and there along its length portions of it 
have been upraised so that they are only some 500 fathoms 
or less beneath the surface. On these last elevations or 
plateaux appear still more elevated areas or banks, the 
summits of which have attained to the level of the “ plane 
of the limiting line of sedimentation,” or, in other words, to 
the level at which reef-building coral organisms can flourish. 
These reef-building organisms have been solely answerable 
for the formation of the Caymans, which are purely coral 
islands. In this respect, therefore, the Caymans differ from 
all the other West Indian Islands except the Bahamas. 
Immediately to the south of the submarine ridge on which 
the islands are situated, and between them and Jamaica, 
there stretches a profoundly deep submarine valley known 
as “ Bartlett’s Deep.” The average depth of Bartlett’s Deep 
is 18,000 feet, but a long trough, which represents its deepest 
part and which is situated, so to speak, at the very foot of the 
stupendous range of which the Caymans form the summit, 
has a depth of 22,000 feet. The water between Cayman 
Brae and Cape Cruz, the nearest point of Cuba, attains to 
a depth of 3000 feet. 
To all intents and purposes, then, so far as the avifauna 
of the Caymans is concerned, we may look upon them as 
pseudo-oceanic islands. They are obviously of very recent 
origin, things of yesterday as compared with the other 
Antillean Islands, and the only way in which they have 
been “ colonized ” has been by the agency of wind and 
marine currents. 
We should consequently not expect to find any very 
marked changes of a specific character, still less of generic 
importance, in the resident land-birds which characterize the 
avifauna of the Caymans. Nor do we find such changes. It 
is, however, remarkable how in many cases these resident 
