ON THE GKOLOGY OF DAUHADOS. 235 



land. From the " ll('])orts on tlie Geology of Jamaici " (Mem. Gool. 

 Survey, iS(ii)) it would appear that the only rocks reeognized a-; 

 ancient coral-reefs by the Surveyors were tliose which border the 

 l)resent coast at levels below 100 feet. Even these are not termed 

 " Kaised coral-reefs," but arc described under the name of " Coast 

 Limestone." Of this the folIovvin<^- account is jj^iven by Mr. Wall 

 ((>y>. cit. p. 109): — " Many of the projecLin<? lieadlands consist of a 

 calcareous deposit enclosing large masses of coral, usually unalterei, 

 and also numerous shells precisely similar to those inhabiting the 

 adjacent sea, but decolourized; several successive beds occur more 

 or less fossilized in the lower part of the series. From such con- 

 siderations it results that the coast-limestone is a comparatively 

 recent formation, and must be referred to the post- Pliocene era, 

 since the organic remains exhibit no variation from the species of 

 the now existing fauna. This group also exhibits the final efforts 

 of those mechanical forces that elevated the various formations of 

 Jamaica to the actual positions in which they are now seen." He 

 states that " the Coast Limestone rarely extends far inland, and is 

 never seen at great elevations." 



The structure of the rock, as exhibited in St. Elizabeth's parish, 

 is thus described by Mr. C. B. Brown (op. cit. p. 209) :—" This 

 formation is composed in places of vast masses of large compound 

 corals embedded in and cemented firmly by carbonate of lime and 

 marl, while in others it is composed of a similar aggregation of 

 coral-masses in a loose, soft, yellowish marl, in places here and there 

 more consolidated .... Besides the numerous fossil corals in this 

 old reef there are many univalve and bivalve shells, together with 

 Echini." 



Few, we think, can read and compare the descriptions of the 

 " Coast Limestones" in Jamaica and San Domingo without being 

 convinced that they occupy similar relative positions, and that they 

 are in all probability similar and contemporaneous deposits. But 

 Prof. Gabb, while adopting the name of '' Coast Limestone" for the 

 raided reefs of San Domingo, has failed to perceive their close 

 analogy with those of Jamaica. He correlates the Domingan 

 *' Coast Limestone" with the formation known as the "White 

 Limestone " in Jamaica, solely on the ground that the " White 

 Limestone " contains corals, and that it decomposes into a red soil. 



The " White Limestone " of Jamaica is described as a massive 

 and bedded formation 2000 feet thick, and occupying some six- 

 sevenths of the total area of the island. The Surveyors were at 

 first inclined to class it as Miocene, but subsequently referred it to 

 the Pliocene. 



At the same time it is possible that this " White Limestone " 

 includes parts of more than one formation, for the descriptions 

 given of it show that while the lower part (500 feet) has fairly con- 

 stant lithological characters, the upper part exhibits very varied 

 structure, Iteing often shelly and coralliferous, and generally almost 

 horizontal, while the lower beds in the same district are tilted and 

 disturbed. Moreover, the Surveyors state that the " Coast Lime- 



