70 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
the rocks of the Coastal Series. They contain few macroscopic fossils 
by which their age can be independently determined, but this is fixed 
by their microscopic fossils and their position between including fossilif- 
erous horizons, — the underlying Cambridge beds and the overlying 
Bowden gravels and marls, 
In general, the Oceanic Series occupies most of the Plateau region, 
which practically includes all the island under 3,000 foet in altitude 
outside of the Blue Mountain district, except its immediate coastal 
borders. In the mountainous region of eastern Jamaica these rocks 
occur as a high piedmontal peripheral border around that end of the 
island. In the western half of the island the beds of the Oceanic Series 
completely cover the old Blue Mountain Series and occupies the higher 
summits of that portion of the island. 
Owing to the elevation of the Plateau region which took place after 
the deposition of these beds, and the subsequent contraction of its 
oceanio borders by erosion and subsidence, the coastward extension of 
the rocks is truncated and partially embedded near the littoral by the 
still later formations of the Coastal Series, which are deposited uncon- 
formably against them. 
The Montpelier Beds. — The Cambridge beds north of Cambridge are 
succeeded by stratified white limestones and marls containing nodules 
of flint. The limestones are of non-crystalline (chalky) texture, and 
usually break with dull, earthy, conchoidal fracture. The texture, frac- 
ture, and presence of flints distinguish this formation from others of 
the great series of white limestones of many ages, which, above the 
Cambridge beds, dominate in the rock structure of Jamaica. 
Concerning the grosser lithology of the Montpelier beds, little can be 
added to the excellent description of them in Hanover and Westmore-’ 
land, given by Charles B. Brown as a portion of the “White limestone,” 
as follows :* — 
` “Tt consists of thin beds of white limestone interbedded with a soft 
white chalky marl, the limestone beds invariably containing nodules of 
flint. The limestones are chiefly soft, but seldom compact or erystal- 
line ; they form thin beds, which vary from a few inches to four feet in 
thickness, and are much disturbed, so as to dip in almost every direc 
tion over small areas. The marl beds being interstratified with thes? 
of course show the same disturbance and dips, and are similar to them 
in thickness. The flints and chert contained in the limestone beds lie 
usually in flattened nodular masses in lines of stratification, and até 
1 Jamaican Reports, pp. 250, 251. 
