SKEATS : CHEMICAL COMPOSITION OF LIMESTONES. 89 
which a Miocene age has been assigned. The continuity of the lime- 
stones is broken by two fairly thick beds of basalt, both probably of 
submarine origin. The beds of basalt are separated by a considerable | 
thickness of a middle yellow limestone, probably of Oligocene or lower 
Miocene age. The specimens analyzed from the sea cliff at Flying 
Fish Cove were collected at definite heights from the sea-level up to 
750 feet, both from the north and south ends of the Cove. Of these, 
the uppermost rock, No. 664, from a height of 750 feet, contains 36.2 
per cent of magnesium carbonate. All the rest are limestones, most 
‘FLYING FISH COVE. 
. Calcium |Magnesium| Insoluble 
Number.| Height. | ¢arponate.| Carbonate.| Residue. Oxper Rocks. 
of which contain only from 3 to 4 per cent of that compound, with 
the exception of No. 595, in which 8 per cent is present. Insoluble 
matter is almost unrepresented in the higher rocks, — No. 549 contains 
.03 per cent, — but the three oldest limestones have from .7 to .8 
per cent of insoluble residue. This circumstance is probably due to 
their close association with the two beds of basalt which occur in this 
part of the island. 
Microscopical. No. 521,— An orbitoidal limestone containing Carpen- 
teria, Orbitolites, Lithothamnion, and the cast of a coral in “mud.” 
Much of the section consists of “wud,” but some has altered to clear 
calcite, and in this part the organisms are represented by dirt lines. 
