HILL: GEOLOGY OF JAMAICA. 123 
With. this exception not a single species of the fauna has been reported 
from the North or South American Mainland. Probably the same fauna 
cours in Cuba and Haiti, judging from papers by G. F. Matthew? and 
Tippenhauer.? It is also possible that it may occur in Guatemala and 
Costa Rica, or even Southern Mexico, where large unstudied Rudistean 
fumas abound, As will presently be noted several of these species of 
Rudistes also occur in the overlying Eocene (Cambridge) beds. 
The most numerous and conspicuous forms of the Jamaican Creta- 
*eous fauna are genera which proportionately have but slight representa- 
tion in the North American Cretaceous, such as the corals, Rudistes, 
Crinwa, and Actzonella, while on the contrary there seems to be an 
Almost entire absence in the Jamaican fauna of such forms as Ammo- 
Nites, Trigonia, Gryphea, Exogyra, Brachiopoda, and Echinodermata, 
Which are so characteristic of the North and South American Cretaceous 
of Atlantic sedimentation. The Jamaican Cretaceous fauna, which is 
the oldest known life of the treat Antilles, is unique. Several Rudistes 
Md two species of corals from these supposedly Cretaceous formations 
*ontinue upward into the beds which are here placed in the Eocene, in- 
ating a gradation of the faunas of these two epochs, as further dis- 
Cussed on a later page. It may possibly be explained upon the hypothesis 
that it lived adjacent to an insular land, separated from the continent 
Y great depths of oceanic water which prevented migration to it of the 
Main littoral fauna in its entirety. These beds represent the expiring 
AYS of the Cretaceous and can hardly antedate the Senonian in age. 
Tun Eocenn FAUNAS. 
: The existence of Eocene strata in Jamaica has hitherto been a ques- 
tion difficult to determine owing to the previous confusion of knowledge 
: the stratigraphy and paleontology. It is our opinion that the Eocene 
S wel] represented by at least two distinct formations, the Richmond 
And Cambridge, and by three, if the Montpelier formation, which is the 
uivalont of tho Vicksburg stage, is included in the Eocene, as has 
Sen customarily done by all American writers until recently, when 
‚Alprin and Dall, following Conrad, have again placed the Vicksburg 
"! the baso of the Oligocene. 
? Canadian Naturalist, 1872, Vol. VII. p. 19. 
Die Insel Haiti, Leipzig, 1893. See Plate preceding page 381. 
N ammonites have been reported in one locality only in Jamaica (page 78), 
leir occurrence there has not been verified or accepted by the paleontologists 
the Survey, 
