:^94 The American Geologist. May. 1897 
article, tlie reinainder being a summary statement of the his- 
tory as developed by others and as verified by my own studies. 
(J(f)ic/i(.sioiis Beached by Previous Observers. A number of 
workers have been in the Bermuda field, and although upon 
^oiiie points there is now quite uniform agreement, there is at 
the sanje time a c-onsidei-able variety of opinion expressed in 
the published papers. 
The first article descriptive of tlie geolog}' of the Bermudas 
is by Nelson.* He points out the fact, to which all later 
workers agree, tiiat the Bermudas are composed of sand de- 
rived from the grinding of coral and other calcareous frag- 
ments, i^y the waves, and then accumulated by the wind into 
the form of sand dunes, thus constituting the present islands 
of Bermuda. He also recognizes a different kind of rock, 
harder and more dense, underlying parts of the island, to 
which he gives the name base rock. 
Rein (Bericht ii. d. Senckenbergische Naturf. Gesellschaft, 
1870, p. 140) has described the geology of Bermuda, but I 
have not been able to obtain his article. 
Jonesj- brings forward evidence of submergence of the Ber- 
mudas to a depth of not less than 4<S feet. This is proved by 
excavations and borings made by the governnient in connec- 
tion with the construction of the great naval dock yard on 
Ireland island. This evidence is obtained from the discovei-y 
of vegetable remains at the depth of 48 feet below the present 
sea-level. He argues from other evidence that this submer- 
gence of 48 feet is merely the minimum. The same author 
has published other papers concerning the geology of the 
Bermudas.;]; 
Wyville Thomson visited Bermuda during the V03'age of 
the Challenger and published a description of some of its fea- 
tures. § Among other things he says that there is really only 
one kind of rock in the Bermudas, namely the consolidated 
leolian sand described by Nelson. He mentions the base rock 
but says that it does not occur everywhere beneath the is- 
*Trans. Geol. See. London, M Ser., V, 1840, 103-123. " 
tNature. VI, 1872. 262. 
J Jones, The Naturalist in Bermuda, London. 1859: also Visitor's 
(iuide to Bermuda. Articles by Jones have also appeared in the Proc. 
and Trans., Nova Scotia lust, of Nat Sci. Neither of these descriptions 
has been accessible, and hence I can make no further reference to them. 
§The Atlantic, vol. i, 1877, 290-347. 
