Geology of the Bermudas. 387 



above the level of the sea, like the volcano of Teneriffe, though not so 

 large or so high. Perhaps more like Martinique, Dominica, and 

 St. Lucia among the Antilles. The size was similar to some of the 

 latter, and there may have been many eruptions as violent as the 

 recent eruptions from Mount Pele and from as lofty a crater. In fact, 

 there must have been a great many eruptions to have built up such an 

 immense cone from the bottom of the deep ocean . . . during the 

 Jurassic period reefs of corals existed as far north as Middle Europe, 

 and the climate in the latitude of Bermuda in the Cretaceous and 

 Eocene was no doubt much warmer than at present. In any case, 

 the final result of the erosion of the larger volcanic cone must have 

 been to form submerged banks or shoals at a suitable depth for the 

 abundant growth of corals, mollusks, etc. 



"George's Banks and Nantucket shoals off Cape Cod maintain 

 themselves in the face of most violent storms ; although composed of 

 only sand and gravel, their shallowest parts rise to within 25 or 

 30 feet of the sea-level. This indicates that the erosive power of the 

 sea waves decreases very rapidly, even at such depths." ' 



It is popularly supposed that Harrington Sound, Bermuda, is the 

 crater of a volcano, but the charted soundings give no support to this 

 idea. What there is deep down beneath we have no way of 

 determining, but the depths are consonant with the features of a 

 submerged valley, and that is all that can be said. 



It is due to the prescience of Nelson that the true character of the 

 present Bermudian rocks is known. At least, I give this statement 

 on the authority of Wy ville Thomson 2 and A. Agassiz. 3 I have not 

 found the actual statement by Nelson himself. 



Whether the primary rocks (moulded on the Bermudian volcano), 

 now deeply submerged, are of the nature of coral-reef structure, cannot 

 at present be ascertained. But all the rocks that can be examined are 

 of ' seolian formation ', a description attributed to Nelson by Wyville 

 Thomson and A. Agassiz. 



II. The Pkevailing Winds. 



The peculiar form of the Bermudas and the greater height of the 

 land on the southern side have been caused by the prevailing winds. 

 Although there are breezes and even at times hurricanes from the 

 north and north-east, the prevailing winds are from the south-westerly 

 direction. This is evident from the fact that the sand-dunes are 

 forming on the south side of the main island, e.g. at Tuckerstown, 

 Elbow Bay, Warwick Long Bay, etc. Nelson says, " Bermuda is not 

 subject to any regular wind ; perhaps to the south-west more than to 

 any other." i 



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

 Sci., vol. xii, p. 55. 



2 Voyage of the " Challenger ", vol. i, p. 307. 



3 A Visit to the Bermudas in 1891, p. 221. " Captain Nelson was the first 

 to call attention to the geolian character of the rocks of the Bahamas and 

 Bermudas. This character saute aux yeux in every direction." 



4 "The Geology of the Bermudas": Trans. Geol. Soc, ser. II, vol. v, 

 pt. i, p. 104. 



