100 THREE CRUISES OF THE “ BLAKE.” 
basin, in the north-eastern parts of which a depth of over 2,500 
fathoms has been obtained. The only line yet run directly 
across the main basin of the Eastern Caribbean has been 
sounded by the “ Albatross” from Curagoa to Alta Vela, a 
small island on the south coast of San Domingo. The deepest 
water found was 2,694 fathoms, — the average depth nearer 
the South American side of the basin being about 2,300 fathoms 
until within a short distance of the land. 
The topography of the Western Caribbean is strikingly dif- 
ferent from that of the eastern basin. "The soundings of Com- 
mander Bartlett have developed an immense submarine valley, 
extending nearly due east for about seven hundred miles, from 
the southern extremity of Cuba towards the Chinchorro Bank, 
off the coast of Honduras. This valley has an average breadth 
of about eighty miles, and an average depth of over two thou- 
sand fathoms. Towards its eastern extremity it attains the 
depth of nearly 3,200 fathoms, and its greatest depth is 3,428 
fathoms twenty miles south of Grand Cayman. So that the 
highest peaks of the chain of mountains skirting the southern 
shore of Cuba, which rise to 8,400 feet, are really 28,000 feet 
above the bottom of this great submarine valley, distant only 
fifty miles in a straight line. As Commander Bartlett has said, 
the little Cayman, Grand Cayman, and Misteriosa banks are 
the summits, just appearing above tide-mark, of a submarine 
range of an average height of nearly twenty thousand feet. 
This deep valley, which has most appropriately been called 
“Bartlett Deep,” forms a loop to the eastward of Cozumel 
Island, south of Pine Island towards the Pickle Bank. To- 
wards the Yucatan Channel, which connects the Western Carib- 
bean with the Gulf, of Mexico, the bottom shelves gradually, 
rising to a height of 1,164 fathoms, — the deepest part of the 
channel between Yucatan and Cape San Antonio. The West- 
ern Caribbean connects with the deep tongue of the Atlantic, 
reaching north of San Domingo through the Windward Passage, 
the deepest part of which is 873 fathoms. 
We could have no better example than the Gulf of Mexico 
affords of the deceptive character of the shore-line for obtain- 
ing a correct idea of a hydrographic basin. (Fig. 59.) "This is 
