﻿GEOLOGY AND PALEONTOLOGY OP THE CANAL ZONE. 



21'^ 



15 genora and ono subgenus of midcllo and upper Oligoeono corals 

 apparently had become extinct in this region. The genus Thysanus is 

 present in the Phocene Caloosahatcheo marl of Florida ;^and in Santo 

 Domingo PlacocyatJius, Slylopliora, Antillia, and Syzygo'pliyllia occur 

 at horizons above that of the Bowdon marl,'whilo the number of species 

 now living increases. The Bowdon marl marks an important change 

 in the character of the coral faunas, a change from an older to a more 

 recent facies. It therefore seems to me that the Bowdon marl can 

 not be considered of Oligocene age, and that it must be referred to 

 the lower Miocene. 



SANTO DOMINGO. 



With regard to the species reported by Duncan from Santo Do- 

 mingo, it will be said that Duncan does not describe the stratigraphy 

 of Santo Domingo, but refers the specimens to the Nivaj6 shale, the 

 superficial or tufaceous limestone, Pos torero shale, Cerro Gordo 

 shales, Esperanza shale, and "the silt of the sandstone plain." The 

 following is a list of the species recorded by him, the geologic forma- 

 tion in which they were reported to be found, and the revised names 

 with annotations: 



Fossil corals reported by Duncan from Santo Domingo. 



