118 



FOSSIL ECHINI OF THE WEST INDIES. 



Antiguan and Anguillan horizons. The Guanica shaly limestone and 

 the Juana Diaz have Clypeaster oxybaphon in common with the Antigua 

 formation of Antigua, where I collected specimens. It therefore appears 

 that the deposits bearing five names in Porto Rico, viz, San Sebastian, 

 Lares, Collazo, and Juana Diaz shale, and Guanica shaly limestone, 

 represent essentially the same horizon, and it is, as Doctor Maury 

 indicates in her table, the Antiguan horizon. The evidence of the 

 echinoids on this problem is interesting in that it accords with the 

 conclusions based on studies of both the corals 1 and the mollusks. 



There are no echinoids definitely referred to the Lares, Aguadilla, 

 and Quebradillas limestones. The two species recorded from the 

 Ponce limestone indicate that it is of Miocene, not Oligocene, age. 

 Recent work in Haiti has shown according to Dr. W. P. Woodring 

 (oral statement) that Ostrea cahobasensis is Miocene, not Oligocene, 

 as indicated in Doctor Maury's table quoted above. 



1 For an account of some corals from the same horizon and an earlier similar correlation, see 

 T. W. Vaughan, U. S. Nat. Mus. Bull. 103, pp. 203, 204, 1919. I first made this correlation in 

 1899. I wish here to call attention to a misrepresentation of my usage of terms in my discussions 

 of Porto Rican horizons. Bela Hubbard in his "Tertiary Mollusca from the Lares district, 

 Porto Rico," N. Y. Acad. Sci. Scientific Survey of Porto Rico, et cetera, vol. 3, pt. 2, pp. 79-164. 

 1920, in the table on p. 79, represents me as having classified under the Pepino formation every- 

 thing from middle Oligocene to his "upper Oligocene," which is probably late Miocene. A very 

 casual reading of my use of the term "Pepino" would have shown Doctor Hubbard that I confined 

 the use of the name to a single horizon, palaeontologically characterized by the fossil corals I have 

 listed in U. S. Nat. Mus. Bull. 103, p. 204. The horizon is considered middle Oligocene. Hill may 

 have intended the term to have a more extensive application, but of this I am not sure. 



