﻿212 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



the Emperador limestone is represented as dipping below tlie Gatun 

 formation on the north side of the Isthmus, and it is exposed almost 

 down to the sea level on the south side. The Culebra formation 

 underlies the Emperador limestone on both slopes, but it is not indi- 

 cated on t]io map on the north slope of the Isthmus. 



Miocene. 



BOWDEN MARL.i 



The point of departure in the consideration of the Miocene is the 

 fauna of the Bowdon marl of Jamaica. The following is a revised 

 list of the species: 



Placoirochus costaius Duncan. 



Splienotrochus new species. 



Placocyathus harretii Duncan. 



alveolus (Duncan.) 



Stylophora granulaia Duncan. 



AsteroswMia profunda (Duncan). 

 Jiilli Vaughan. 



Stephanocoenia intersepia (Esper), also living. 



Aniillia walli Duncan. 



Thysanus exceniricus Duncan. 

 elegans Duncan, 

 new species. 



SyzygopTiyllia gregorii (Vaughan). 



Siderastrea siderea (Ellis and Solander), also living. 



Goniopora new species. 



Ponies haracodensis Vaughan. 



Acropora new species. 



This fauna indicates somewhat deeper water than that in which 

 the species mentioned on preceding pages lived; but the presence of 

 Stephanocoenia intersepta, Siderastrea siderea, Acropora new species, 

 a massive species of Goniopora, and Poriies haracodensis, furnish evi- 

 dence in favor of the conclusion that the depth probably was not so 

 much as 20 fathoms. The most striking feature of this list is that it 

 contains the names of two species still living in the Caribbean region, 

 in this respect differing from all the other faunas previous!}^ consid- 

 ered in this paper. The Bowden not only marks the introduction of 

 species that persist in the West Indian region, but as neither in 

 Jamaica, Santo Domingo, nor Cuba, have species of Asirocoenia, 

 Siylocoenia, Leptomussa, Aniiguastrea, Faviies, Lepioria, Troclioseris, 

 Leptoseris, Haloseris, Pironasiraea, Mesomorpha, Cyaihomorpha, 

 Diploastrea, Asireopora, Actinacis, or Porites (Synaraea) been found 

 in beds of the same ago as or younger than the Bowden, these 



* For an account of the strati?raphic relations of the Bowden marl, sen Hill, R. T., The geology an<? 

 physical geography of Jamaica, Mus. Comp. Zool. Bull., vol. 34, No. 1, pp. 226, with 35 plates, 189f 

 (especially pp. 82-86, 145-152). 



