Bulletin 35 
286 
138 
fore. Hill’s observation that Orbitoides are not found above the 
Eocene is, in my opinion fully borne out b}' the facts here as well 
as in Jamaica. 
I consider that the rocks occurring in the Marbela Mine 
down to the depth of 160 feet represent the Nariva series, while 
the lower beds represent the Naparima oceanic deposits. These 
last differ in some respects from the Naparima oceanic beds, and 
the difference may be due to the deposition of the sediments in a 
shallower sea on the flanks of the cretaceous ridge crossing the 
middle of the Island and lying to the north of the great Naparima 
Anticline. In mj’ first note already quoted I described the differ- 
ence in these words ; “A very noticeable difference is that the 
material of the oceanic beds when washed j’ields a residue con- 
sisting almost entirely of Foraminifera (chief!)’ globigerina), 
while that of the Marbela deposit consists of small pieces of slaty- 
looking and ferruginous materials, the foraminiferal fauna 
being much scantier than that of the oceanic beds.” While 
admitting a large amount of variation in composition in the 
Page 54 
Naparima rocks, this ma)’ be held to be true generall)" of the 
oceanic beds. We have to assume therefore a shallower sea and 
a greater quantit}’ of muddy sediment in this area than in that to 
the south of Naparima Hill. {See 1113^ Section in Journal of the 
Geological Societ\’, 1892, p. 522). 
From Mr. Wilson I received some additional samples of a 
hard sandstone which appear to have come from a lower depth 
than the Orbitoides bed, some 220 feet deep. These contain fos- 
sils but not in a determinable condition, and the rock is so hard 
that there is no means of extracting them. I believe, however, 
that these rocks are the ver}’ base of the tertiaries or top of the 
cretaceous. I consider therefore, that the rocks at the Marbela 
Mine represent the equivalent in time of the whole Naparima 
series and extend downwards from the Miocene inclusive to the 
Eocene and top of the cretaceous. They were however deposited 
