276 VAUGHAN : CORRELATION OF TERTIARY FORMATIONS 



La Cruz marl. This marl is of midde Miocene age, as it appears 

 to be slightly higher stratigraphically than the Burdigahan 

 Bowden marl of Jamaica. The fossils obtained in it are described 

 in my paper on the fossil corals of Central America, Cuba, and 

 Porto Rico, and in unpiibHshed manuscripts by J. A. Cushman 

 and C. W. Cooke. Among the corals are the genera Stylophora, 

 Orbicella, Solenastrea, Thysanus, Siderastrea, Goniopora, and 

 Porites. Solenastrea, Siderastrea, and Porites contain species that 

 I have been unable to distinguish from hving West Indian species; 

 but the genera Stylophora, Thysanus, and Goniopora are extinct 

 in the Atlantic Ocean. The type exposure is along the railroad 

 leading east from La Cruz, which is on the east side of Santiago 

 Bay. The formation is well exhibited in the bluffs along the east 

 side of the Bay north of the Morro. The material is a yellowish, 

 very calcareous marl, or an argillaceous limestone, which is as a 

 rule well bedded. ( 



Only one point on the correlation table appears to need special 

 comment, that is whether the limestone containing Orthophrag- 

 mina on Haut Chagres and at David, Panama, should be referred 

 to the uppermost Eocene or to the basal Oligocene. It has been 

 stated above that the Ocala limestone contains large stellate 

 species of Orthophragmina, and that I collected a similar species 

 in St. Bartholomew. Of the Eocene age of these deposits, of the 

 typical Brito formation in Nicaragua, and of certain limestones 

 containing Orthophragmina in Cuba there seems to be no reason- 

 able doubt. But, according to Douville, the small stellate Ortho- 

 phragmina (subgenus Asterodiscus) ranges upward into the lower 

 Oligocene. The association of Asterodiscus, and small, even 

 non-stellate, species of Orthophragmina, with species of Lepido- 

 cyclina that at some localities are associated with a coral fauna of 

 middle Oligocene affinities has inclined me to the opinion that 

 certain peculiar species of Orthophragmina occur in deposits of 

 early Oligocene age. Dr. Cushman, however, is disposed to 

 regard the beds in which these species of Orthophragmina were 

 found as of Eocene age. At present the evidence is not decisive, 

 and additional studies are needed. 



