300 BULLETIN OF THE 
forming, in fact, the outline of a large island, which would include the 
whole of the Virgin Islands, the whole of Porto Rico, and extend some 
way into the Mona Passage. The 100-fathom line similarly forms a 
large plateau, uniting Anguilla, St. Martin, and St. Bartholomew. It 
also unites Barbuda and Antigua, forms the Saba Bank, unites St. 
Eustatius, St. Christopher, Nevis, and Redonda. It forms an elongated 
plateau, extending from Bequia to the southwest of Grenada, and runs 
more or less parallel to the South American coast from the Margarita 
Islands, leaving a comparatively narrow channel between it and the 
100-fathom line south of Grenada, so as to enclose Trinidad and Tobago 
within its limits, and runs off to the southeast in a direction also about 
parallel to the shore line. At the western end of the Caribbean Sea 
the 100-fathom line forms a gigantic bank off the Mosquito coast, ex- 
tending over one third the distance from the mainland to the island of 
Jamaica. The Rosalind and Pedro Banks, formed by the same line, and 
a few other smaller banks, denote the position of more or less important 
islands which must have once existed between the Mosquito coast and 
Jamaica. On examining the 500-fathom line, we thus find that Jamaica 
is only the northern spit of a gigantic promontory, which once extended 
toward Hayti from the mainland, reaching from Costa Rica to the 
northern part of the Mosquito coast, and leaving but a comparatively 
narrow passage between it and the 500-fathom line encircling Hayti, 
Porto Rico, and the Virgin Islands, in one gigantic island. The pas- 
sage between Cuba and Jamaica has a depth of 3,000 fathoms, and that 
between Hayti and Cuba is not less than 873 fathoms, the latter | 
being probably an arm of the Atlantic. The 500-fathom line connects, 
as a gigantic island, the banks uniting Anguilla to St. Bartholomew, 
Saba Bank, the one connecting St. Eustatius to Nevis, Barbuda to 
Antigua, and from thence extends south so as to include Guadeloupe, 
Marie-Galante, and Dominica. This 500-fathom line thus forms one 
gigantic island of the northern islands, extending from Saba Bank to 
Santa Cruz, and leaving but a narrow channel between it and the 
eastern end of the 500-fathom line running round Santa Cruz. As 
Santa Cruz is separated from St. Thomas by a channel of forty miles, 
with a maximum depth of over 2400 fathoms, this plainly shows its con- 
nection with the northern islands of the Caribbean group, rather than 
with St. Thomas, as is also well shown by the geographical relations of 
its Mollusca, The 500-fathom line again unites, in one gigantic spit 
extending northerly from the mouth of the Orinoco, all the islands to 
the south of Martinique, leaving Barbadoes to the east, and a narrow 
passage between Martinique and the islands of Dominica and St. Lucia. 
