SKEATS: CHEMICAL COMPOSITION OF LIMESTONES. 93 
348 and No. 350, from heights of 325 and 310 feet, contain See rey 
only 2.6 and 5.2 per cent of that compound. 
Calcium Magnesium Calcium 
Number. Height. Carbonate. Carbonate. Phosphate. 
308 350° 60.63 39.22 15 
348 325’ 97.4 ae Loe 
350 310’ 94.8 6.2 
Microscopical. No. 348. — A rather cavernous limestone, largely con- 
sisting of crystalline semi-opaque cement, and in which Globigerina occurs 
rather plentifully. 
Rocks from the Interior of the Island (Miocene ?). 
LinE oN THE Roap TO Murray Hity. — This road starts from a 
point where it meets another road at right angles to it running down 
to West White Beach. The limestones were collected in vertical 
sequence up the slope, from 650 feet to 1100 feet, almost at the summit 
of Murray Hill. 
MURRAY HILL. 
: Calcium | Magnesium 
Height. | Carbonate. | Carbonate. 
60.34 40.02 
59.8 40.2 
96.0 4.0 
97.1 2.9 
95.7 4.3 
Chemical. — The two highest specimens, No. 378 and No. 379, from 
heights of 1100 and 1000 feet respectively, contain about 40 per cent of 
magnesium carbonate, but the remaining three specimens are limestones, 
in which the amount does not reach 5 per cent. 
Microscopical. No. 378.— Lithothamnion can still be recognized, 
and a gray meandrine dolomitic “ silt ” suggests the former presence of 
corals. The amount of finely crystalline dolomite is very large, but 
cavities are lined with clear rhombohedra, and no zoning is seen. 
No. 360. Almost entirely composed of very small rounded or fusi- 
form fragments, with a few larger rounded pieces, cemented by clear 
° 
scalenohedral crystals of calcite. The appearance of these fragments 
