TOPOGRAPHY OF THE EASTERN COAST. 105 
Islands, rising from twelve to sixteen thousand feet above the 
bottom of the Eastern Caribbean, with the many passes between 
them, — the sieve through which the warm surface water of 
a great part of the equatorial current is forced by the trade- 
winds ? 
We may imagine for a moment that we are taking a bird’s-eye 
view of this whole district, and look down upon the compara- 
tively level plains of the Atlantic to the eastward of the Barba- 
dos. These plains rise from a depth of three thousand fathoms 
to the hundred-fathom line in a distance varying from three 
hundred and fifty to two hundred miles on the eastward of the 
Windward Islands; the highest summits of these islands (five 
thousand feet) are only separated by narrow passages, апа thus 
form a more or less continuous chain of volcanic peaks. On 
the westward, toward the Caribbean, the slope is more rapid; 
a depth of one thousand to fifteen hundred fathoms is reached 
at a comparatively short distance to the leeward of the Lesser 
Antilles. The chain is narrowest between Martinique and Do- 
minica, widening gradually towards Grenada and Tobago to the 
south, and somewhat faster towards the Virgin Islands, which 
are separated from the Santa Cruz, Saba and Sombrero banks 
by a deep basin opening into a narrow cañon of about one 
thousand fathoms, with a shallow connecting ridge between 
Santa Cruz and Porto Rico. 
The mountain chain, of which San Domingo, Porto Rico, and 
the Virgin Islands form the summit, has a steep slope to the 
north, dropping at the eastern extremity, at a distance of less 
than one hundred miles, to a depth of three thousand fathoms. 
The two-thousand-fathom line runs along the eastern edge of 
the Bahama Bank, a distance of less than fifteen miles, and 
forms a steep edge to that face of the bank, while the thousand- 
fathom line cuts off a few isolated outside patches, and extend- 
ing far to the westward, beyond the Windward Passage, forms 
the mouth of the funnel of the old Bahama Channel. 
The southern slope of this part of the West India Islands 
chain is fully as steep as the northern. At the western ex- 
tremity of San Domingo, the southern line of mountains extends 
toward Jamaica, and. that part of the chain is deflected to the 
