STRATIGRAPHIC PALEONTOLOGY. 



99 



fauna, consisting of about 600 species from a single locality, is more diver- 

 sified than the faunas of either the Cercado or Gurabo formations, but is 

 more similar to the Gurabo fauna than to the Cercado. There is no 

 faunal or stratigraphic evidence to sustain Doctor Maury's assumption 

 that the Bowden fauna is stratigraphically a mixed fauna, though it is 

 less homogeneous than either the typical shoal-water Cercado or Gurabo 

 faunas. 



The Gurabo corals that occur also in the Bowden marl and in the marls 

 at Baracoa and Matanzas, Cuba, are listed in the following table : 



Gurabo corals. 



Bowden. Baracoa. Matanzas. 



Stylophora granulata Duncan 



Madracis decactis (Lyman) 



Madracis mirabilis (Duch. and Micht.). 



Asterosmilia profunda (Duncan) 



Asterosmilia hilli Vaughan 



Stephanocoenia intersepta (Esper) 



Thysanus n. sp. a 



Agaricia dominicensis Vaughan 



Porites baracoaensis Vaughan 



Siderastrea siderea (Ell. and Sol.), which occurs at Bowden, was not col- 

 lected in the Gurabo, but as it was found in the underlying Cercado forma- 

 tion and in the overlying Mao Adentro limestone the failure to obtain it in 

 the Gurabo was probably accidental. Another Bowden species, Pla- 

 cocyathus barretti Duncan, was collected by Doctor Maury's party in the 

 Samba Hills at an altitude of about 540 feet (station 7787), and Mr. Condit 

 collected on Rio Yaque del Norte at station 8702 a specimen that is referred 

 to in the list (p. 147) as Placocyathus barretti Duncan var., but this may be a 

 varietal form of P. variabilis Duncan. The number of species now known 

 from the Bowden marl is 17, 2 and 9 of these occur in or range through the 

 Gurabo formation. A species of Goniopora at Bowden is very close to 

 G. jacobiana Vaughan, which occurs in the Gurabo and in the Mao Adentro. 

 Another Bowden species, Antillia walli Duncan, was collected on the 

 south side, a mile north of Azua (station 8609). 



The correlation by Vaughan of the La Cruz marl of Cuba with the Gurabo 

 formation appears to be correct, as every species identified in it except 

 Thysanus excentricus Duncan, a Bowden species, is found also in the Gurabo 

 formation, but the La Cruz marl may be the equivalent of the Mao Adentro 

 limestone. It now seems that the faunal differences between the marls at 

 Baracoa and Matanzas, Cuba, and the La Cruz marl at Santiago, Cuba, 

 may be due to difference in ecologic conditions rather than to difference in 

 age, the marl at Baracoa and Matanzas and that at Bowden having been 

 deposited in somewhat deeper water than that in which the La Cruz marl 

 and most of the Gurabo formation were deposited. 



1 Maury, C. J., Bull. Am. Paleontology, vol. 5, p. 433, 1917. 

 * Vaughan, T. W., U. S. Nat. Mus. Bull. 103, p. 211, 1918. 



