HILL: GEOLOGY OF JAMAICA. ra 
rarely in beds themselves. They are not connected continuously, but 
are in long hollow flat masses, and have all the appearances of having 
been deposited around or in the substance of some organic form which 
Was embedded in the limestone. These flints are chiefly of a brownish 
pink, brown, and gray colors. At Knockalva and other places in the 
vieinity the limestone contains small veins of silica, and also has become 
80 thoroughly impregnated with that substance as to be completely 
changed into a siliceous limestone." ! 
Microscopic examinations show that the calcareous beds consist of 
Organic oceanic material, and are composed of the shells of Foraminifera, 
Occasional sponge spicules, and fine crystals and amorphous particles of 
carbonate of lime, like those usually found in all chalky oceanic deposits. 
No terrigenous material whatever has been found in any specimens 
9xamined. The Montpelier beds are singularly free from molluscan or 
Other visible fossils, except a large species of Orbitoides in its lower 
beds, Nummuline have also been found. 
William Hill? has studied microscopically a specimen of white lime- 
Stone, Hanover County, which undoubtedly came from the Montpelier 
beds. This, according to Jukes-Browne and Harrison,’ is an oceanic 
deposit in which “ Thick-shelled Globigerin®, similar to those of the 
Barbados rocks, aro conspicuously abundant, and one or two Radiolarians 
can be seen in outline." 
Some of the flints are also black or gray in color and flattened, oblong 
in shape, like those of the Upper Cretaceous of England and Lower 
Cretaceous of Texas; others are round and opalescent. The whitened 
exterior surfaces of many specimens are masses of silicified Forami- 
hifera, — Orbitoides, Nummuline, and Miliolide, — and these can be 
Made out in the interior of some of the specimens collected from Mont- 
Pelier Hill. Similar occurrences of Foraminifera coating the flints have 
been noted from St Mary. In plaees they occur in great abundance as 
requently described in the Jamaican Reports, and are found in no 
Other formation so far as we have observed. Oceasionally there are 
also hard siliceous lumps in the limestone, which suggest that secondary 
alteration into flints may have been possible. In general, these seem 
to be silicified lumps of organio skeletal remains, Several spocimens of 
. 1 The description above given refers to Brown's lower division of the white 
limestone (our Montpelier beds); the upper beds (our Brownstown beds) are more 
Compact and massive, and contain fewer interstratified marls. 
* Quart. Jour. Geol. Soc. London, 1891, Vol. XLVII. pp. 248, 249. 
3 Ibid., 1892, Vol. XL VIII. p. 180. 
