148 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



(Hydrographic Chart No. 357, Admiralty Chart No. 1^872). The 100 

 fathom line is about seven miles from the east coast. The bank has twenty- 

 seven fathoms on the east edge, diminishing to twenty about half a mile 

 from the shore. On the western side of the island the edge ot the bank 

 is not more than two thirds of a mile from the shore. 



The eastern and southern shores of Grenada are skirted by wide frin- 

 ging coral reefs, following the deep indentations which characterize that 

 part of Grenada. Between the island and the 100 fatliom line a number 

 of irregular banks rise from the main bank, with from seventeen to 

 eighteen fathoms upon them, from near the 20 or 30 fathom line, the 

 summits probably of islets and islands no longer reaching the surface. 



The Grenadines consist of about one hundred islands and rocks ex- 

 tending for sixty miles between Grenada and St. Vincent, none of them 

 attaining a height of more than eleven hundred feet. The smaller islets 

 and islands are many of them fringed with reefs, or protected on the eastern 

 faces by barrier reefs. 



Carriacou ^ (Hydrographic Chart No. 357, Admiralty Chart No. 2872), 

 Little Martinique, Little St. Vincent, Union, and Prune Islands are pro- 

 tected on their eastern faces by curved barrier reefs with deep water 

 between the reef and the shore (one to seven fathoms), or by fringing 

 reefs. The Tobago Cays are the centre of a complicated system of coral 

 reefs, forming the fringing reefs of Tobago and of the smaller adjacent 

 cays ; between the islands extend broad patches of coral heads. The 

 Tobago Cays (Hydrographjc Chart No. 357, Admiralty Chart No. 2872) 

 are in the centre of a great narrow horseshoe-shaped barrier reef, the 

 horns of which are nearly two and a half miles apart. Outside to the 

 eastward are the isolated reef patches known as Egg Reef and World 

 End Reef, which rise within the 6 fathom line and are similar to the 

 isolated reefs so common upon the bank, but most of which are covered 

 with coralline and coral sand too deep for the vigorous growth of corals. 



Cannouan (Hydrographic Chart 357, Admiralty Chart No. 2872) is 

 flanked on the east face by a barrier reef with a belt of water from one 

 to six fathoms inside of it. On the islands to the north the coral reefs 

 are less vigorous. From- Moustique to Carrfacou there are a series ot 

 narrow, elongated ridges with from fifteea to twenty fathoms of water 

 upon them, rising from the 20 to the 30 fathom line and following in 

 general the 100 fathom curve. 



The ridge of which the Grenadines, St. Lucia, and other Windward 

 Islands form the summits broadens out gradually as we pass northward 



1 The largest of the Grenadines, rising to a height of nearly one thousand fee*^- 



