590 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



Dall said, in 1903, regarding the age of the Bowden marl of 

 Jamaica: 1 "It is perhaps with the Oak Grove sands, or between tho 

 Chipola and the Miocene, that the position of the Bowden fauna 

 would be marked most plausibly against the Tertiary column of 

 Florida formations." 



This correlation has essentially been made by students of other 

 groups of organisms, but instead of considering the Bowden of 

 Oligoccno age, they refer it to the Miocene. W. P. Woodring, in a 

 recently published summary of his conclusions based upon a study of 

 the Bowden pelecypods, 2 says: "Though many of the post-Chipolan 

 elements are found among the characteristically tropical groups, 

 yet the introduction of superspecific groups, some of which are not 

 exclusively tropical, can hardly be disregarded. Tho Bowden 

 pelecypods are distinctly younger than those of tho Alum Bluff 

 faunas, as these faunas are now known. It may be suggested that 

 the Bowden fauna is Burdigalian, that is, lower Miocene in the sense 

 of most American stratigraphers." 



Dr. J. A. Cushman, from his study of the Foraminifera, and 

 Messrs. Canu and Bassler from their investigations of the Bryozoa 

 consider the Bowden fauna Miocene. My opinion, based upon the 

 fossil corals (see pp. 212, 213 of this volume), is the same as that 

 of the authors mentioned. Until the results of Miss Gardner's work 

 on the Mollusca of the Alum Bluff formation are tabulated and com- 

 parisons made with the Bowden fauna, only approximate correlation 

 is practicable. It is my opinion that the Bowden is equivalent to a 

 horizon high in the Alum Bluff, perhaps about that of the Shoal 

 River marl. In other words, the Bowden corresponds to upper 

 rather than to lower Burdigalian. 



There are in Santo Domingo at least three Miocene horizons, 

 according to the results recently obtained there by Miss C. J. Maury. 3 

 She transmitted the Foraminifera, corals, echinoids, and Biyozoa 

 to me for study in connection with the investigation of the strati- 

 graphic paleontology of Central America and the southern United 

 States, and Miss M. J. Rathbun has delivered to me a manuscript 

 in which she has included descriptions of the fossil Crustacea col- 

 lected by Miss Maury. Besides Miss Maury's report on the Mollusca, 

 I am able to use Doctor Cushman's report on the Foraminifera, 

 my own on the corals, Doctor Jackson's on the echinoids, Messrs. 

 Canu and Bassler's on tho Bryozoa, and Miss Rathbun's on the 

 Crustacea. Miss Maury's zone II on Rio Cana is the same horizon 

 as the Bowden; and she considers her zones G and I to be the samo 



» Dall, W. H., Tertiary fauna of Florida, Wagner Free Inst. Sci. Trans., vol. 3, pt. 0, p. 1582, 1903. 



* Woodring, W. P., The pelecypods of the Bowden fauna, Johns Hopkins Univ. Circular, March, 1917, 

 pp. 242-254, 1917. 



» Maury, Carlotta J., Santo Domingo type sections and fossils, Bull. Amer. Paleontology, vol. 5, pp. 

 165-459, pis. 28-C5, 1917. 



