112 TRANSACTIONS OF THE [jAN. 18, 



SO numerous in the southern two-thirds of the lagoon as to 

 make passage dangerous to the last degree for any except small 

 boats. They are less numerous in the northern third, which is 

 almost bisected by a ridge forming the Three Hill shoals. 



The reef itself has some deep spaces either wholly enclosed or 

 with very narrow channels leatling to the ocean or to the lagoon. 

 The largest, at two or three miles north from St. George, is 

 double, each portion more than two square miles and a-half. 

 The depth varies from seven to twelve fathoms, while that on 

 the enclosing portion of the reef is from shoal to four fathoms ; 

 the uiiiting strait is less than one-eight of a mile wide and that 

 to the ocean is of equal width and only seven or eight fathoms 

 deep. Somewhat nearer St. George is another basin, wholly 

 enclosed, more than half as large as Harrington sound and from 

 seven to ten fathoms deep, while the depth on the surrounding 

 reef is from shoal to four fathoms. Each of these has islands of 

 small size covered by from one to three fathoms of water. Many 

 similar though smaller basins are on other parts of the reef. 

 The peculiarities of Castle harbor are reproduced in the curious 

 bays indenting the southern border of the reef. If the hills of 

 the land ai-ea were planed off so as to give to each a level top, 

 the resulting contour would simulate closely that of the floor of 

 the lagoon. 



The distribution of channels through the reef is equally sug- 

 gestive. A ridge, covered with shoal to five fathoms, extends 

 from the north side of Chub cut to Somerset island and is the 

 northern boundary of a basin extendiug southward to the reef, 

 six to ten fathoms deej) and containing islands, some of which 

 are bare at low tide. This basin communicates with the ocean at 

 the northwest by Chub cut, only four to five fathoms deep, and 

 at the southeast by Hogfish cut, from four to seven fathoms 

 deep. Several other channels lead across the reef, but with one 

 exception they head up against shoals. The ship channel at the 

 northeast corner of the area, ver^^ narrow and with four to nine 

 fathoms, leads into the open northern third of the lagoon and 

 follows a clear course to Spanish point on Hamilton island, 

 where it turns westward and follows a difficult course to Grassy 

 bay, at the end of Ireland island. Then, by means of the Stag 

 channel, recently deepened to sixteen feet, it crosses the barrier 

 extending from Ireland to Hamilton island and eventually 

 reaches Hamilton harbor. 



This barrier separates the lagoon from the basins within the 

 "hook." It is about a mile and a half long, and is marked by 

 Cobbler's, Lapstone, Hogfish, Stag, Magazine and other islands 

 separated by channels, three to fifteen feet deep. Immediately 



