AGASSIZ: BERMUDAS. 231 



THE SOUNDS AND LAGOONS. 



Plates II., IV., VI., VII., XIV., ami XXVII. 



The sounds are sinks and depressions filled with sea water, as was first 

 suggested by Rein, and none of tliem are secondary atolls. They owe 

 tlieir origin either to the breaking through of low saddles dividing sinks 

 from outer lagoons, or to subsidence, allowing the water of adjacent 

 lagoons or the sea to flow in over separating ridges, or to both these 

 causes. 



Professor Heilprin gives an excellent description of the rapid waste 

 which the islands are undergoing, and of the formation of the sounds, on 

 pages 36 and 37 of his Bermudas. 



The improbability of the sinking of the roofs of large cavernous areas to 

 form the sounds, as has been suggested by Rein ^ and Fewkes,^ does not 

 militate against local disruptions on a limited scale, of which, as Heilprin 

 states, there is abundant evidence.^ 



The lagoons of the south shore between Tuckerstown and Newton Bay 

 are brackish pools separated by low hills from the sea (Plate XIV.). In 

 many places it would require comparatively sliglit inroads of the sea, or 

 but little subsidence, to change them into diminutive harbors or sounds, 

 similar, but of course on a smaller scale, to Castle Harbor or Harrington 

 Sound. The shore platforms of Harrington Sound and Castle Hai-ljor 

 are similar to the ledges which extend off the clitfs from the outer shores 

 of the islands (Plates VI., XXVK.). 



Harrington Sound seems to have been formed in exactly the same 

 way as the smaller liarbor indentations of the coast. Its shores present 

 all the phenomena of disruption by waves exiiibited by the outer shores, 

 although in a less degree. The action of the sea is of course much less 

 powerful, yet is sufficient to have undercut the cliti's, and in some places, 

 as on the nortli sliore of the sound, they are fully as high as many of tlie 

 more striking cliffs formed on the sea faces outside by the splitting off 

 of large slices of the pcolian hills. 



We find in Harrington Sound islands, islets, and many honej'combed 

 ledges (Plate XXVII.), pinnacles, and mushroom-shaped rocks, due to 



1 Kein, Rericht., 1870. 



2 Fewkes, J. W., Troc. Bost. Soc. Nat. Hist., 1887, p. 518. 



3 Bermudas, p. 45. 



