TOPOGRAPHY OF THE EASTERN COAST. 99 



ing from St. Christopher to Bird Island and about to the lati- 

 tude of the Grenadines, showing considerably less than a thou- 

 sand fathoms, with fifteen hundred to two thousand fathoms on 

 each side. 



The eastern boundary of the Eastern Caribbean is formed by 

 the dumb-bell shaped plateau, from which rise the Windward 

 Islands. (Fig. 58.) These extend in a gigantic arc from Som- 

 brero and Santa Cruz to Grenada, Tobago, and Trinidad, leav- 

 ing broad, shallow passages between the islands to the north 

 of Dominica, with the three comparatively deeper straits sepa- 

 rating Dominica, Martinique, St. Lucia, St. Vincent. We next 

 come to the still shallower passages over the Grenadines Bank, 

 and the deeper passage between that bank and Tobago. This 

 island, as well as Trinidad, and all the Leeward Islands to the 

 north of Venezuela, lie within the hundred-fathom line.^ They 

 are all only outposts of the South American continent. From 

 the Gulf of Venezuela to the mouth of the Orinoco the hun- 

 dred-fathom line is about ninety to one hundred and twenty 

 miles from the South American coast. 



The thousand-fathom line, which extends diagonally across 

 the Eastern Caribbean from the south-western extremity of San 

 Domingo to a point about one hundred miles north-west of 

 Aspinwall, runs towards the Venezuelan coast, and follows the 

 line of the hundred-fathom curve, with the exception of an 

 indentation from the deep water, extending to the southward 

 and eastward, between Curagoa and the mainland. It also 

 follows closely the general trend of the south coast of San 

 Domingo, Porto Rico, and bears to the west of the Windward 

 Islands, being nowhere more than about forty miles from the 

 coast-line, and usually from ten to fifteen miles on the lee side 

 of the Windward Islands to the south of Guadeloupe. 



Little is yet known of the depth of the main basin of the 

 Eastern Caribbean ; but from the absence of islands and banks, 

 it is probable that it is, like the Gulf of Mexico, a huge oval 



^ The "Albatross," in 1884, ran a line from ten to forty miles. "Albatross," 



from Curapoa to the mainland in a south- Hyclrographic Report, 1884, J. R. Bart- 



erly direction, the greatest depth found lett. 

 being 738 fathoms at a distance ranging 



