232 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



erosion or to the solvent action of the sea, difiering in no way from those 

 made along the nijrth and south shores of the islands. Along its shores 

 there are numertus ledges running out froui or parallel with them, ex- 

 tending between the small rocky promontories, which if cut oft" would 

 form a series of patches close to sliore similar to those which extend from 

 the north shore inside of the banks towards the outer ledge flats and 

 upon them. Gorgonians, corals, and other growths, have settled upon 

 the ledges since the time when they and the saddles have sunk or liave 

 been eroded to their present level, giving the sea access into the interior 

 of the various sounds so characteristic of the Bermudas. This is admi- 

 rably shown by the cutting of tlie sea into St. George Harbor, so as to 

 give access to it both from the outer and inner waters of the bank. 

 These passages are narrow, so that corals do not get a sufficient suj)p]y 

 of fresh water, and hence are far less couunon than on the shelves of Cas- 

 tle Harbor, which is freely connected with the sea on its southern expos- 

 ure. In Harrington Sound the connection with the lagoon is still less 

 open, a narrow cut on the north being the only opening through which 

 the inner waters of the bank gain admission to it. Castle Harbor in the 

 same way is connected freely with the sea on the soutJj, and but slightly 

 with the inner waters of tlie bank, through the same opening which con- 

 nects tliem with St. George Harbor. 



A narrow cut separates Somerset Island, wliich forms the western 

 boundary of Great Sound, from the main island. Tliis sweeps round to 

 the eastward and forms the southern flank of Port IJoyal I!ay, which is 

 separated from Great Sound by the line of islands extending outward 

 from Tucker to Darrel Island (Plate II.). 



The de])th of water in tlie sounds is veiy considerable, not only in the 

 sounds themselves, but also in the inner waters of tlie reef, which liave 

 been called lagoons, but are hardly such in the sense in which that term 

 is understood. It would greatly conduce to accuracy to call the inner 

 basins of deep water — surrounded on one side by tlie outer ledges of 

 the reef, and on the other either by tlie connecting patches of ledges or 

 by the islands in part — sounds also, for such tliey undoubtedly are, and 

 were sounds similar to those now existing and known as Great St)und, 

 Port Royal Bay, Hamilton Bay, St. George Harbor, Castle Harbor, and 

 Harrington Sound. 



In Great Sound we find from ten to eleven fathoms. In Harrington 

 Sound as much as twelve fathoms is found in several spots. In the outer 

 sounds we do not as a general rule find so luroat depths. What we may 

 call the Brackish Pond and Bailej- Flats Sound has a gencial depth of 



