HILL: GEOLOGY OF JAMAICA. LIT 
Molluscan species of the adjacent continental borders found habitat in 
the littoral waters of the island prior to the late Oligocene (Bowden) 
epoch, when the bottom of the region was sufficiently elevated to per- 
Mit the migration of shallow water species over wide arcas of the 
tropical seas and to connect the Jamaican littoral fauna with that of 
the mainland. Forms which abound in the preceding epochs, especially 
the corals and Foraminifera, are those adapted to wide oceanic migration. 
these conditions have produced in these earlier faunas a peculiar mix- 
ture of genera, comprising oceanic species and a few littoral mollusca 
Which had found accidental foothold and acquired peculiar characters 
through long isolation, — the whole making a faunal assemblage quite 
foreign to those known in other typical areas of the world upon which 
Stratigraphic and age classifications have been founded, although re- 
taining generic criteria sufficient for positive age determination. Pale- 
Mtologists, unaware of these conditions, have naturally failed to obtain 
the collections from the island a correct impression of the strati- 
Saphie significance of its fossils. 
In view of the confused condition of current published conceptions 
of the paleontology of Jamaica above set forth, it will be impossible in 
the present chapter to straighten out the confused synonomy of species, 
à task which must be left to other specialists. Our principal endeavor 
will be to point out the true stratigraphic position of the material 
hitherto described, thereby making it of geologic as well as biologic 
Value, and then, by aid of the larger amount of new material collected 
ay us, present some deductions which may be of service to those who 
in the future undertake the special task of further advancing the 
Paleontology of Jamaica. 
ORETACEOUS. 
Blue Mountain Series. Lower Division. 
From the occasional limestones and marl beds occurring in the vast 
sickness of tuffs and conglomerates of the lower division of the Blue 
3 lountains, the following fossils have been collected, most of which have 
A decided Cretaceous facies. 
? l'oraminifera : Rotalia or Pulvinulina!; *Orbitoides (T) ?; Ellipsac- 
on *Nummulites (0.3 
orals : Cladocora jamaicaensis, Vaughan ; *Diploria conferticostata, 
! Identified by R. M. Bagg. Collected by Robert T. Hill. 
2 Identified by Woodward. Collected by Jamaican Surveys, 
