448 PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 6, 



in Antigua : there is some doubt about the accurate determination 

 of the Antiguan form, on account of its state of preservation ; but, 

 as far as the structures can be seen, the fossils are specifically the 

 same. 



Species of the genera Astroria and Coeloria are found in the Chert, 

 and are remarkable for the beauty of their silicification, the original 

 hard tissues being turned into homogeneous black flint, whilst the 

 interspaces are filled with opalescent silica. These are the first 

 fossils of the genera which have been noticed ; and the species are 

 remote from Coeloria labyrintluformis, which is said by Dana to 

 exist round the Bermudas and in the Red Sea. 



It is very doubtful whether the species of Coeloria and Astroria 

 (see note attached to the description of the species, p. 424) said to be 

 of West Indian origin are really so. Astroria Sinensis is commonly 

 offered for sale as a West Indian specimen, with other corals de- 

 cidedly belonging to the East Indian fauna. The Red Sea Astroria 

 astrceceformis, and Astroria stricta from the Straits of Malacca, have 

 very close structural alliances with the new species from the Chert 

 of Antigua, one of which {Astroria polygonalis) is a well-marked and 

 most important species. 



The Antiguan sj>ecies prove how gradual is the passage from a 

 perfect Astrcea to a sinuous Coeloria, through the fissiparous Astrcece 

 already mentioned and the various Astrorice. 



It will be found difficult to maintain the present genera intact 

 when the anatomy of these forms is better understood ; for in one 

 specimen there are such variations of thickness of wall, depth of 

 fossa, and length of series, as seriously interfere with its satisfactory 

 classification ; and it is most probable that in most specimens, when 

 they were entire, similar variations existed. 



The Alveoporce are reef-corals, and although there are species 

 common to the limestones of Antigua, Jamaica, and San Domingo, 

 still the genus is no longer West Indian, but Pacific. These are the 

 first instances of fossil Alveoporce. 



The large Rhodarcea is allied to JR. Raulini of the Dax Miocene, 

 though but slightly ; all the recent species are found in the Chinese 

 and Australian Seas, not in the Caribbean. 



There are none of the species of those genera which are so strongly 

 represented in the present West Indian Seas amongst any of the col- 

 lections of Antiguan fossil Corals in the British Museum, the Museum 

 of the Geological Society, or the Museum of Practical Geology. For 

 example, the following well-known recent West Indian genera are 

 quite unrepresented : — 



Eusmilia. 



Colpophyllia. 



Prionastraea. 



Oculina. 



Ctenophyllia. 



Manicina. 



Siderastrsea. 



Porites. 



Dendrogyra. 



Diploria. 



Parastraea. 



Madrepora. 



Lobophyllia. 



Cladocora. 



Phyllangia. 



Millepora. 



Symphyllia. 



Cyphastraea. 







There is a Mceandrina in the Chert which has very short series, 

 and is very sinuous, but its details are too deficient to enable me to 

 determine its specific affinities. 



