HILL: GEOLOGY OF JAMAICA. 187 
feet above its level — in fact not over fifty — although the whole of the 
white limestones of that island rising to heights of 2,000 feet or over, 
have been erroneously attributed to coralline origin by various writers.’ 
Similar low elevated reefs occur completely around the island of 
Haiti, as described by Gabb in a manuscript in the library of the 
United States Geological Survey, which recounts the results of a 
second visit to the island after his large report on San Domingo had 
been published, in which he. had erroneously attributed all the white 
limestones of the region to coral reef origin. The writer has seen many 
of these reefs on the coast of San Domingo, and they are in general 
analogous to those of Cuba and Jamaica, although the three subsiding 
stages of the latter island have not been differentiated. Concerning 
Porto Rico and the Virgin Islands we have no data proving the exist- 
ence or non-existence of elevated reefs around their borders. According 
to Cleve's description of the Virgin Islands,? and my. observations of 
Barbuda, the geological position of the elevated reefs of the Great 
Antilles is generally oceupied in these islands by the granular white 
limestone with molluscan remains previously described, Sombrero, 
as described by Julien however, is an exceptional locality in this 
general region, as it is composed of elevated reef rock, the Bulla lime- 
stones and lagoonal material There is some evidence in the reports 
of MeClure* and Henry that elevated reefs occur on the island of 
St. Croix. 
The elevated. reef phenomena of the Lesser Antilles are varied and 
peculiar, presenting different aspects in Barbados and on the leeward 
and windward sides of the Caribbee Islands. On the windward side 
of the Caribbees true elevated reefs of the modern type are found bor- 
dering Desirade, Marie Galante, and Grand Terre-Guadeloupe, as noticed 
by Maclure in 1817.° Here they occur as in the Western Antilles as 
simple undeformed benches of reef rock standing from six to ten feet 
above the level of the sea, The reefs of Guadeloupe were described by 
Duchaissang in 1847,’ and were considered by him to be recent in age, 
and synchronous with the upland formations of that island which con- 
tain the remains of fossil man. 
1 Gabb, Crosby, and others. 2 Cleve, loc. cit., p. 18. 
3 On the Geology of the Key of Sombrero, W, L, Annals of Lyceum of Nat. 
Hist. of N. Y., Vol. VIL pp. 251-278. 
4 Trans. Phila. Acad. Nat. Sci., 1817, Vol. I. p. 188. 
5 Amer. Journ. Sci., 1839, Vol. XXXV. p. 78. 
$ Jour. Phila. Acad. Nat. Sci., 1817, Vol. I. p. 135. 
* Bull. Soc. Géol. de France, 2d Series, 1842, Vol. IV. Pt. 2, pp. 1093, 1094. 
