158 Mr. De la Beche on the Geology of Jamaica. 



timate, from barometrical observations, to be 2340 feet above the level of the 

 sea, thick beds of very compact gray siliceous sandstone are seen forming a 

 high cliff to the west of the house* ; these strata cross the river, into the bed 

 of which large blocks of sandstone and the conglomerate have fallen. 



There are some marly strata above Hopewell, a little further down the river 

 than Middleton, in which veins of white and rose-coloured gypsum occur ; 

 these strata are mixed with others of sandstone, and the whole seems to con- 

 stitute a part of the same formation with the red and gray sandstones and con- 

 glomerates composing the upper portion of the Hope Valley section ; for rocks 

 similar to the latter again come in between Hopewell and the limestones of 

 Mount Pleasant. The beds here mentioned present a mixture of thick strata 

 composed of siliceous sandstones, with conglomerates, formed of rounded 

 pieces of older rocks, and cemented by the same kind of siliceous sandstone, 

 occasionally interstratified with slaty sandstone. The dip of these strata is 

 generally at a considerable angle to the S.W., they are in some places per- 

 pendicular, and appear to have suffered much disturbance. 



At Mount Pleasant a blackish gray compact limestone comes in, some of 

 the beds of which are traversed by numerous veins of calcareous spar, in ge- 

 neral appearance very much resembling many beds of the carboniferous lime- 

 stone in the vicinity of Bristol, such as that of Clifton, &c, 1 observed what 

 appeared to be encrinal remains in the Mount Pleasant limestone, as also sec- 

 tions of bivalve shells. These limestone beds dip at about an angle of 75° to 

 the eastward, which is by no means conformable to the mass of red-sandstone 

 and conglomerate rocks in which they seem in some measure included ; yet a 

 collection of similar limestones, not much more in the whole than 50 or 60 

 feet thick, crosses a valley near the Mount Pleasant beds in an East and West 

 direction, and seems to be connected with them. The same kind of limestone 

 beds are found near Flamstead House, in the Port Royal Mountains. The 

 dip is not clearly shown at this place ; but the limestones are associated in the 

 same manner as those near Mount Pleasant, and appear to be a continuation 

 of them ; for patches of compact gray blue limestone may be seen in several 

 places between Flamstead and the Botanical Garden. Now Mount Pleasant 

 is situated in a north-westerly direction from Flamstead, and this is precisely 

 that of the red-sandstones and conglomerates of the district, for their direction 

 is N.W. and S.E. ; so that the Mount Pleasant limestones may be referred to 

 the place I have assigned them, notwithstanding the dip. Thick beds of yel- 



* The mountain which rises to the west of the house, and of which this cliff forms a part, is, 

 according to my barometrical observations, 3752 feet above the sea. 



