BERMUDA. 21 



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 "iEolian formation" in his account of the geology 

 of the Bermudas. t Jukes observed that in Heron Island the 

 main strata of calcareous rock composing the island dipped out- 

 wards 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 construction of 

 forts. The red fragments of Spoiidylus 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 fragments cemented together, as 

 usually occurs in coral islands. The sand rock contains various 

 fossils, most abundantly a land snail (Helix) now abundant in the 

 islands, and a much larger one, now extinct, but closely resem- 

 bling the present species in other respects than size. The bones 

 of turtles and birds are also found in the rock, and all the 

 common marine shells of the islands. The rock, when exposed, 

 is honeycombed by the action of the rain, and that of sea water, 

 and on the coast its surface has a remarkable corroded appear- 

 ance. It is eaten into cup-like hollows all over, separated from 



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

 1875, p. 182. 



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

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



