88 



OK THE TOFOaiiArilY AX1> GEOLOGY 



(p. 34) : " Limestones are rare, do not exceed ten to twenty feet in thickness, arc 

 extremely compact, and their fossils nsnally partially or entirely transformed into 

 highly crystalline spar." Had they been describing the Dominican deposits instead, 

 they might have nsed the same words. 



In 18G0 Mr. L. Barrett, then colonial geologist of Jamaica, published a short note 

 in the Journal of the London Geological Society,'^*" in which he describes the Cretaceous 

 deposits of that island and mentions the existence of Inoceramus, H{2:)imrites, Nerinea 

 and Bulla, but does not attempt to fix the exact age. Still later, Mr. Etheridge pre- 

 pared a memoir for the geological report of Jamaica,! in which he discusses all of 

 the information obtained to date. By a clea*' and exhaustive examination, he proves 

 that the Jamaica Cretaceous is most probably on or very near the horizon of the Gray 

 Chalk. The total number of fossils collected by the Jamaican Geologists is 13 species of 

 Mollusca, 1 Echinoderm, 5 corals and 1 Rliizopod ; but little better luck than we have had. 



Dr. P. Martin Duncan has elaborately studied and described the fossil corals of the 

 West Indies,^ having had large collections from nearly all of the islands at his disposal. 

 He is quoted by Mr. Etheridge as anticipating the discovery of Cretaceous rocks in 

 Santo Domingo on account of some corals from the Miocene of the Cibao, which 

 seemed out of place in that formation. || • 



From a long familiarity with the " JS^ivaje shale," which is simply the middle part 

 of our Miocene, I am incline to doubt Dr. Duncan's specific determination of the coral, 

 rather than accept his conclusion. All of the Cretaceous debris in the Miocene of 

 Santo Domingo — and it occurs abundantly — exists as highly metamorphosed pebbles ; 

 the metamorphic action seeming to have been completed before the deposition of the 

 overlying fossiliferous strata. In fact Dr. Duncan himself § is not perfectly sure of 



* Loc. cii. Feb. 1860, p. 334. 



f Appendix V. Geol. Report, p. 300 et seq. 1869. . ' - ... 



\ Quart. Jour. Geol. Soc, vol. xix. p. 400, and vol. xx. p. 30. 



I Etheridge, loc. cit. j). 308, says, "Dr. Duncan has also stated his belief that "the Hippurite limestone exists in 

 the neighboring-island of Santo Domingo, basing this oinnion upon the fact that corals having very decided lower 

 cretaceous affinities were noticed in Miocene Strata " in that island. He noticed having found the Euroi^ean lower 

 chalk coral Asiroccoiia dccapliyUui in the Jamaican Miocene ; Phyllocania sculpta, from the Gosau and Uchaux beds, 

 was also found in the Nivaji shale in St. Domingo, associated with four other species of Turonier affinities in the 

 same shale." 



§ P. J. G. S. vol. 19, p. 450. He says : "In the yellow shale there is a ramose coral which, i^rovisioually is classed 



with PJiylloeania. With one exception its structural characteristics agree with a very remarkable coral, which has 



been referred to many genera, having been ca'led by Goldfuss, Madrepora limbata, by Brown Oculina limhata, by 



M'Coy Uemmastrma limhata, and by Milne-Edwards Stylina limbata. Our species has no columella visible, and 



although it is notorious that the little shai-p collnmelhe of Stylinm constantly fall out, still I have considered it 



advisable to disregard this and to classify the form with PhylloccBnia, and to state the probability that other specimens 



will determine the presence or absence of a columella. Another species so closely resembles Phyllocmnia sculpta 



(Michelin, Zooph, pi. 71, fig. 1 and 3), that it can only he considered a variety with a tile-shaped corallum." The italics 

 ai'e mine. 



