Geology of the Bermudas. 393 



a period of depression. Some of these now lie 12 or 16 feet above 

 the sea, and by the fine character of the materials and good condition 

 of the shells appear to have been formed in quiet waters and not 

 tossed up by hurricanes. These delicate shells and Foraminifera (such 

 as are found at depths of from 3 to 5 fathoms) indicate that after 

 deposition the beds containing them have been raised 20 to 30 feet or 

 more above their previous level. 1 



As these deposits are well developed at Devonshire Bay, Verrill has 

 proposed the name of Devonshire Beds for them. They contain some 

 twenty species of Pelecypoda and thirty-one of Gasteropoda, all 

 marine. 2 At Hungry Bay delicate shells of Mollusca — Ccecum, etc. — 

 were found entire in the finer layers of rock. 



Verrill gives the following species as not certainly known to 

 be living in Bermudian waters at the present time : Strombus 

 accipitrinus, Lam. ; Fasciolaria distans, Lam. ; Scala sp. ; Venus, 

 a large lamellose species; Turbo (Livona) pica (L.) ; Callista (? macu- 

 lata) ; Phacoides Pennsylvanicus, var. Somersensis, Verrill ; Balanus, 

 a large massive species; ? Mycetophyllia Lamarckiana, Ed. & Haime ; 

 ? Ifceandra areolata (L.), Oken ; Melitta testudinata (Klein). All 

 the beach rocks are not of this age — which Verrill places about the 

 Champlain or Post-Glacial Period — but some are doubtless being 

 formed still and also destroyed by storms that occasionally occur with 

 great violence. (The Champlain or Leda Clay period belongs to the 

 Glacial Period according to Prestwich.) 



Agassiz, however, groups all these beach rocks as of recent origin 

 and formed since the islands attained their present level. His own 

 observation leads him to look upon the beach rock of the Bermudas as 

 consisting mainly of the larger and heavier seolian materials, which 

 either have not been carried so far or blown to so great a height as 

 the lighter aeolian sand. 3 He considers that all the beach rock has 

 been formed from recent shell-sand by the hardening action of salt 

 water and rain. In England such beach rock is forming on the sea- 

 shore near the cliffs on the west of Harlyn Bay by the infiltration of 

 rain-water through the blown shell-sand cliffs to the beach. A shelf 

 some 40 yards long and 2 or 3 yards wide is thus in process of 

 consolidating. Some of the Bermudian beach rock may have been 

 formed in this way, but Verrill seems to have made out a very good 

 case for the distinct character and intermediate date of some of these 

 marine beach beds as being of a precedent origin to the formation we 

 have next to consider. 



These Devonshire Beds would lie unconformably against and not 

 overlie the higher parts of the earlier Pliocene AValsingham Beds, if 

 the fact is that these latter form a spine for the whole length of the 

 islands, since we have seen that the latter beds are of a height of 

 65 feet above O.D. at Prospect Hill and no doubt elsewhere, whereas 

 the submergence suggested by Verrill maybe put at only 14 to 18 feet. 

 (3) The Paget Formation. The last series of rocks overlies the 

 Devonshire Series, and is generally composed of consolidated soft 



1 Verrill, " The Bermuda Islands : Geology": Trans. Conn. Acad. Arts Sci., 

 vol. xii, p. 189. 



2 Op. cit., pp. 76, 190. 3 A. Agassiz, op. cit., p. 225. 



