B. J. L. Guppy — West Indian Tertiary Fossils. 405 



thongh containing some species in common with, that of the Miocene 

 deposits, will be found hereafter to have a very much larger number 

 of species than we have hitherto noticed. In the San Fernando beds, 

 whose age we now state as Eocene, are many moUusca whose con- 

 dition is such that, although we may venture to assign to them their 

 generic position, it would be unwise to describe new species from 

 such imperfect material. As regards the Foraminifera, I believe that 

 the differences between the faunas of the several deposits depend 

 more upon bathymetrical conditions than upon anything else. 



The determination of the geological age of the Jamaica beds and 

 of the remarkable relations of the fossil fauna of the West Indian 

 Miocene to that of Europe and the living fauna of the eastern seas, 

 is strikingly supported by the new fossils now described. We have 

 a Murex, an Ovuhmn, a Cassis, and a Fasciolaria, whose nearest 

 congeners are European Miocene and Asiatic recent ; a Scalaria, 

 previously described indeed, but from, inadequate material, whose 

 relations are similar,^ and a Naticina, a genus almost extinct in the 

 West Indies, but whose present distribution is along the path pointed 

 out as that of the migration of organized beings during the Tertiary 

 period from^ America to the Paci'fic Ocean through North Africa and 

 South Europe. 



Among the Jamaica shells there are few, e.g. Turho castaneus, 

 Strombus jmgiloides, and Flicatula vexillata, which, like the Conus 

 fuscocingulatws of the European Miocene, retain traces of the colour- 

 ing which ornamented them while living. It is only where the 

 strata are of such composition as to be extremely favourable to the 

 preservation of molluscan remains, that such a circumstance could 

 occur. In Jamaica and Haiti the Miocene formations have been 

 remarkably suited to' this end, and hence we have from them a 

 series of organic remains scarcely surpassed in beauty even by 

 those of Bordeaux, Dax, or Paris. In Trinidad the shells of similar 

 age are for the most part extremely altered, and their characters 

 more or less obliterated. It is therefore fortunate that we have 

 those of Haiti and Jamaica upon which i& found aiid rectify our 

 determisnations of the Trinidad rocks and fossils of like age. 



§ II. — D^:scRiPTi0JF O'F THB Foesiii&. 



Myalcea (Diacria) Vendryesimya, PI. XVII. Figs. 2ffl, 26. 



Shell elongate, smooth ;. both valves somewhat in'flated, but the su- 

 perior one more sO' than the O'ther i terminated on each side by two 

 sharp mucrones, and posteriorly by a narrow curved mucro not so long 

 as the body or main portion of the shell. Lips everted, the inferior 

 one bordered exteriorly by a raised ridge, which towards the lateral 

 mucrones gradually becomes confluent with the edges of the lips. 

 Length 5 mm., of which the terminal mucro forms about 2. Breadth 

 nearly 3 mm. 



Eelated to H. inflexa and lahiata of D'Orbigny. — It differs chiefly 

 in being more inflated, especially the inferior valve, and in being 

 narrower behind the lateral mucrones — a character, it would seem, of 

 some importance in this genus. 



