144 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
Cambridge, Montpelier, and Moneague Eocene formations. They art 
missing in all subsequent strata. 
It is also now apparent that Dall’s recent statement,’ based upon 
Guppy's material from alleged Miocene beds (Oligocene), to the effect 
that “ Orbitoides mantelli has not been found in the West Indian species," 
is incorrect, and we must accept the occurrence of this species as iden 
tified by those eminent authorities, T. Rupert Jones? and R. M. Bagg: 
Concerning the other Foraminifera of the Cretaceous and Eocene strat? 
it can be said that Alveolina is a genus which elsewhere “ begins in the 
Cenomanian, continues in extraordinary profusion, and becomes a most 
important rock builder in the Eocene ® of the Paris Basin, Libyan Desert, 
and Greece, is also reported by Jones in “ Alveolina limestone ” from 
Crofts in the northeast corner of Clarendon, —a locality of the White 
Limestone which we have not had the opportunity of visiting. 
The Orbitoides, Nummulinse, Alveolina, Operculina, and Globigerin® 
are Foraminifera which have been found only in the Blue Mountains 
Montpelier, and Cambridge beds of the Cambridge section. ‘hes? 
genera, with the exception of Globigerina, which ranges extensively 
through geologic time, from the early Mesozoic to the present, have 
their typical and highest development elsewhere in the Vicksburg stag?- 
of the Eocene Tertiary. In accordance with Dall's usage, the Vicks 
burg beds, to which the Montpelier beds are undoubtedly equivalent 
are now considered the base of the Oligocene. . When we consider th? 
stratigraphic evidence concerning the containing formations, there is 2° 
reason to believe that their occurrence in Jamaica is later than in thi 
epoch. 
The Mid-Tertiary Antillean revolution, with its mountain making 
expansion of land areas, and rearrangement of barriers and enclosure® 
which closely followed after the Montpelier subsidence, seriously affocted 
the conditions of life and produced changes of environment affecting 
the molluscan and other faunas of the whole Tropical American regio? 
After this revolution, the littoral mollusca, as it next appears in the 
Bowden formation, presents new and distinct facies, characterized by the 
appearance in Jamaican waters of species which also occur on the co» 
tinental borders, many of which are still living. This fauna, constituto? 
the chief bench mark in the whole system of Jamaican N eo-Tertiaric$ 
just as the Cambridge does for the Eo-Tertiaries. 
1 Proc. U. S. Nat. Mus., 1896, p. 329. 
2 The Geologist, London, 1864, Vol. VIT. pp. 103-105. 6 
3 Eastman's “Text Book of Paleontology," by Karl A. von Zittell, London, 189» 
p. 26. 
