236 MR. JUKES-BROWNE AND PROF. HARRISON 



stone " often rests conformably on and passes down into the upper- 

 most member of the White-Limestone series {e.g. in the ])arishes of 

 Metcalfe and St. Mary). It is not unlikely, therefore, that the so- 

 called " White Limestone" includes high-level reef limestones of 

 post-Pliocene date which have a greater general resemblance to 

 some portions of the older limestone series than to the more recent 

 coral-rock of the coast. It is, indeed, remarked of the " Coast 

 Limestone '"' in the parish of Westmoreland that it here much re- 

 sembles the " W^hite Limestone " in outward appearance. Both in 

 Cuba and Barbados the difference between the rock of the lower 

 and higher levels is very great, and if there were not a continuous 

 series of platforms illustrating the process of alteration, the 

 idea of their belonging to different formations might have been 

 entertained. 



It is a curious coincidence that after the above was written we 

 found the following passage in Mr. W. 0. Crosby's paper on the 

 " Elevated Reefs of Cuba": — " On the island of Jamaica precisely 

 similar reefs have been observed at an elevation of 3000 feet ; and 

 Mr. Sawkins, in his Report on the geology of that island, says that 

 the reef limestone has a maximum thickness of not less than 

 2000 feet, and that the oldest of it was formed after the close of 

 the Tertiary period." 



It does not appear that Mr. Crosb}" is personally acquainted with 

 Jamaica, and he is certainly not justified in drawing such inferences 

 from Mr. Sawkins's Report. The rock referred to is evidently the 

 " White Limestone," but Mr. Sawkins never calls it " Reef Lime- 

 stone," nor does he make any such statement as to its age. 



As we have already suggested, it is not unlikely that some of the 

 so-called White Limestone is raised-reef rock, but it does not follow 

 that the whole of it is. Por further evidence on this point see 

 Mr. Hill's 2nd Appendix to this paper. 



(g) Cuba. — The raised reefs of this island are apparently on a 

 larger scale than in any of the other islands, and are even more 

 conspicuous than in Barbados. The first to recognize the true cha- 

 racter of the raised reefs of Cuba appears to have been Dr. Daubenj:, 

 for we find the following notice of them in his work on Volcanos 

 (second edition, p. 468) : — " Humboldt speaks of calcareous rocks 

 found near Matanzas which belong to the Jura formation, but 

 during the cursory visit which I paid to that locality in 1838 I 

 only observed an extensive coralline limestone of recent date up- 

 heaved from the sea. It contains large caverns, and is filled with 

 a profusion of very beautiful corals, as well as of shells belonging 

 to species now existing. It forms a kind of belt along the northern 

 coast, not only between Havana and Matanzas, but I believe for a 

 much greater distance, and is probably one of the most extensive 

 coral-beaches to be found in any part of the world." 



The best and most recent account of the Cuban reefs is by Mr. 

 W. 0. Crosby, from whose description we quote the following 

 paragraphs* : — 



* Proc. of Boston Nat. Hist. See. rol. xxii. (1882) p. 124. 



