Corals and coral islands.

218

CORALS AND CORAL ISLANDS.

group, and those of Long Cay and Rum Cay are described as
equalling those of the Bermudas.
The Bahamas differ from ordinary atolls more in the
great size of the two western banks, and the wide distribution and high heapings of the wind-drift deposits, than in any
other characteristics. Some peculiarities are due also to the
position of the reefs, - one end resting on a sea-border plateau and the other extending out into the deeper waters of
the ocean. To the westward, a rise of three thousand feet
would make one land of Florida, Cuba, and the Bahamas; but
the Bahamas to the eastward would still be a line of oceanic
islands. As to evidences of recent elevation nothing is positively known. The great extent and height of the drift-made
dry land appears to indicate a long resting at the present
level.
The Bermuda or Somers' Islands. -The Bermudas are
what remains of a large atoll, as first announced by Lieutenant
Nelson; and this atoll is the most remote from the equator
of any existing. It lies in deep seas between the parallels
1 Transactions of the Geological Society of London, 1840, v., 103.
The following are other important publications on the structure of the Bermudas: The Reports of the Challenger Expedition of 1873 and 1876, by Sir Wyville
Thomson, London, vol. i.; " The Naturalist in Bermuda," by John Matthew Jones,
with a map and illustrations, London, 1859; also, by the same, "A Visitor's Guide
to Bermuda;" Observations on the Bermudas, in Nature for 1872; and on the geological features of the Bermudas in the Proceedings and Transactions of the Nova
Scotia Institute of Natural Science, 1867; A paper on the Bermuda Reefs by
Dr. J. J. Rein, in the Senckenberg. Ber. naturforsch. Gesellschaft, 1869-70. and
Verhandlung des I. deutsch. Geographentages fiir 1881, Berlin, 1882. There are
also two valuable American contributions to the Geology of the Bermudas, one by
Prof. William North Rice, of Middletown, Conn., 32 pp. 8vo, being Bulletin No. 25
of the U. S. National Museum, 1884; and a volume by A. Ieilprin, of Philaldlphia, entitled "The Bermuda Islands: a contribution to the Physical History and
Zoology of the Somers' Archipelago," a handsoncly illustrated work of 231 pp. Svo,
treating of the coral reefs, and also of the zoology, and discussing at length the
coral-island problem, with conclusions favoring, like those of Professor Rice. the
Darwinian theory.