AMERICAN AND WEST INDIAN FAUNA AND FLORA. lll 
of things existing along the Lesser and Greater Antilles in a 
former period, we are at once struck by the fact that the Virgin 
Islands are the outcropping of an extensive bank. The great- 
est depth between these islands is less than forty fathoms, a 
depth which is found on the bank to the east of Porto Rico, — 
the hundred-fathom line 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 hundred-fathom line similarly forms a large 
plateau, uniting Anguilla, St. Martin, and St. Barthelemy. It 
also unites, as separate banks, Barbuda and Antigua, forms the 
Saba Bank, and unites St. Eustatius, St. Christopher, and Nevis. 
It unites Redonda with Montserrat. It forms an elongated 
plateau, from Bequia to the southwest of Grenada, and runs 
more or less parallel to the South American coast from Mar- 
garita Island, leaving a comparatively narrow channel between 
it and the hundred-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 hundred- 
fathom line forms a gigantic bank off the Mosquito coast, 
extending over one third the distance from the mainland to 
the island of Jamaica. The Rosalind, Pedro, and a few other 
smaller banks, limited by the same line, denote the position of 
more or less important islands which may have once existed 
between the Mosquito coast and Jamaica. On examining the 
five-hundred-fathom line, we thus find that Jamaica is only the 
northern spit of a gigantic promontory, which perhaps once 
stretched toward Hayti from the mainland, reaching from Costa 
Rica to the northern part of the Mosquito coast. There is left 
but a comparatively narrow passage between this promontory 
and the five-hundred-fathom line which encircles Hayti, Porto 
Rico, and the Virgin Islands, in one gigantic island. 
The passage between Cuba and Jamaica has a depth of over 
three thousand fathoms, and that between Hayti and Cuba is 
not less than eight hundred and seventy-three fathoms in depth. 
The five - hundred - fathom line connects the bank uniting 
Anguilla to St. Barthelemy, the Saba Bank, the one which joins 
