1 8 



BERMUDA. 



action of various eddies of wind, or the burying of a small 

 dune in the edge of a larger one. ]n some cases, an already 

 hardened dune, after having suffered denudation by the action 

 of the waves, has become buried in a more recent sand mound, 

 and this process may have been repeated several times, as the 

 accompanying diagram, showing the arrangement of bedding 

 in some rocks at Castle Harbour, will show. I saw no rock 

 in Bermuda with an inclination in its bedding of more than 

 35° 30', which is not much more than the slope of some of the 

 sand-hills. 



Dana terms this calcareous sand-rock, " Drift sand-rock." * 

 Nelson terms it "/Eolian formation" in his account of the 

 geology of the Bermudas. t Jukes observed that in Heron 



STRATA OF SAND ROCK, CASTLE HARBOUR, BERMUDA. 



Island the main strata of calcareous rock composing the island 

 dipped outwards from the longitudinal axis of the island towards 

 the shore, north and south, with an inclination of from 8° to 

 10°, and Nelson observed similar dispositions of the strata at 

 Bermuda. 



The rock of Bermuda presents all degrees of consolidation, 

 from beds of mere unagglutinated friable sand to extremely 

 hard and compact stone. The main component rock is a good 

 deal softer than Bath stone. A much harder rock occurs at 

 two places in the islands only, and is quarried for the construc- 

 tion of forts. The red fragments of Spondylus shell are 

 especially well preserved in it. A bed of lignite was found at 

 a depth of 40 feet below sea level in excavating for dockyard 

 purposes, being evidently an ancient peat bed, such as those 

 which now occur in the islands, overwhelmed by the sand. 

 Besides these primary sand rocks, a conglomerate is being 

 formed on the shore in some places, composed of beach frag- 



* Dana, " Corals and Coral Islands." Sampson Low & Co. London, 

 1875, p. 182. 



t Major-Gen. Nelson, R.E., " On the Geology of the Bermudas." 

 Trans. Gcol. Soc. London, Vol. V. 1840. 



