64 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
of its parts are occasionally recognized. In reports on the other parishes 
it has been termed “White Limestone,” and “ Calcareous Marl” of St. 
Thomas-in-the-Vale, Metcalfe, and St. Mary, and referred to the Cre- 
taceous, Eocene, and Miocene ages. ; 
The term “Yellow Limestone ” is peculiarly applicable to these beds, 
but unfortunately this name was also applied, through the erroneous 
correlation of Wall,’ Etheridge,? and others, to the beds of Oligocene 
age at Bowden, as shown in the Introduction of this report. In view of 
these facts, it is unwise to continue further the term “Yellow Lime- 
stone" as a formation name for any of the Jamaican beds. 
The highest point at which the Cambridge beds are known to occur 
is 3,000 feet, near Luidas Vale, St. Catherine Parish. 
There are several paleontologic and stratigraphic features of the 
Cambridge beds which are peculiar, and will require more extensive 
field work for final explanation. "We have reason to believe that the 
beds are not connected, but occur in broken patches, which, at least in 
their lower portion, like the Cretaceous beds, represent sporadic colonies 
of lime making organisms, which found temporary foothold at intervals 
during a period of turbulent deposition generally unfavorable to a large 
development of marginal life. These deductions are based upon the 
fact that in no two localities are the sequence of sediments or associa- 
tion of species identical, while in others the beds do not appear between 
the Richmond and Montpelier. Furthermore, the fossiliferous horizons 
of the Lower Cambridge are so like some of the Cretaceous that the 
one has been frequently mistaken for the other. The mixture of Cre- 
taceous Rudistes and Eocene corals and mollusca at Catadupa, as seen 
by us, and of Orbitoides and Rudistes in Portland, as noted by Barrett,’ 
indicates a transgression of Cretaceous life into the Eocene, and further 
denotes the anomalous nature of this formation. 
These beds, while showing sedimentary relations to the Richmond, 
undoubtedly represent a transitional step in the deepening which later 
produced the Montpelier formation. In some places it seems perfectly 
conformable beneath the latter, while again, as shown by Brown and 
seen in several places by us, they are unconformable, These apparently 
irreconcilable conditions can probably be explained upon the hypothesis 
that the island was undergoing subsidence during the Cambridge epoch, 
although parts of it were then dry land, which was still further covered 
1 Quart. Jour. Geol. Soc. London, Vol. XXI. p. 56. 
2 Jamaican Reports, p. 811. 
8 Quart. Jour. Geol. Soc. London, 1860, Vol. XVI. pp. 324-826. 
