a ae 
1908-9. ] THE GEOLOGICAL CONNEXIONS OF THE CARIBEAN REGION. 389 
elevation of the Isthmus of Panama or of the Andean region, or both. 
cut off the Caribean area from the Pacific. The same explanation 
applies also to certain of the molluska, upon some of which I shall 
proceed to offer some remarks. I believe that crustacea and echinoder- 
mata will, when examined, furnish additional evidence in the same 
direction. 
Arca patricia Sow. The likeness of this species to 4. grandis of the 
Pacific was noticed by Carrick Moore and Sowerby in treating of the 
Haitian fossils. Sowerby described it as distinct under the name given 
above, but Gabb insisted upon its identity with the Pacific shell. In 
reporting on the Tobago fossils (Bull. Bot. Dep., Trinidad, 1903, page 
541), I gave my reasons for keeping it under a separate name. This ark 
is highly characteristic of the Haitian miocene, and it occurs abundantly 
in the miocene beds of Trinidad and Tobago. It has no neer relation 
in the existing fauna of the West Indies. No large ark now 
inhabits the Atlantic. It is remarkable, moreover, that this shell, 
together with Purpura woodit, Rostelaria inornata and a few others, have 
not been found in the miocene of Jamaica. 
Chama antiquata Dall. I only mention the name of Chama arcinela 
here to observe that Dall has provided a new name for the miocene form 
and places the species in the section Echinochama Fischer. Thus in his 
list the West Indian miocene shell stands as Echinochama antiquata 
(Florida Fossils, Wagner Inst., Part VI, page 1404). Its Pacific analogue 
is Chama californica Dall. But the name Arcinela is sufficiently good as 
a sectional name, and thus for the present the name of the miocene form 
may stand as Chama (Arcinela) antiquata Dal. 
Rostelaria tnornata Gab. Oneof the most remarkable fossils of the 
Haitian miocene is that named by Gabb Orthaulax inornatus. It is, I 
believe, congeneric with Strombus amplus Brander of the European 
eocene, aS noted in my paper on the Haitain fossils (Journ. Geol. Soc., 
Lond., 1876,page 520). Dall places it under the genus Roste/aria with 
two other miocene species of the validity of which I am doubtful, even 
though Dall has spent a good deal of labour in making out their charac- 
ters (Florida Fossils, Wagner Inst., Part I, page 170). Dall is not 
-inclined to entertain my suggestion that the shell may be referred to 
Fiipochrenes, but that the differences are of doubtful importance can be 
seen by a comparison of Sowerby’s figures in Min. Conch., Vol. V, Tab. 
CCXCVITI, CCXCIX, and CCC, Gabb’sin Proc. Acad. N.S. Phil., 1872, 
Pl. IX; F. 3-4, and mine in Journ. Geol. Soc., Lond., 1876, Pl, XXVIII, 
