SKEATS: CHEMICAL COMPOSITION OF LIMESTONES. 95 
at intervals along the road, do not contain more than about 5 per cent 
of magnesium carbonate. . 
Microscopical. No. 708. — A meandrine cast of a coral in calcite and 
sections of Polytrema planum fill most of the slide. The semi-opaque 
matrix is seen under the high power to consist of calcite crystals. 
- Calcium Magnesium 
Height. Carbonate. Carbonate. 
700’ 94.8 6.2 
700’ 95.1 4.9 
880’ 66.4 
95.0 
94.9 
95.9 
95.3 
96.8 
96.7 
96.0 
No. 705. A section of a fragmental limestone containing perfectly 
fresh-looking and unrolled Orbiterdes neo-dispansa, besides Polytrema 
Amphistegina, Orbitolites, Carpenteria, Lithothamnion, set in a matrix 
of calcite. 
Isolated Analyses from the Interior of the Island. 
Vicinity oF PHospHate Hii. — Three specimens were collected from 
the slopes of the hill just below the bed of phosphate which forms the 
capping to the summit. All three specimens are dolomitic, but it is an 
interesting circumstance, considering their relation to the phosphatic 
capping, that none of them give any appreciable reaction for phosphate 
with ammonium molybdate. 
Chemical. 
Calcium Magnesium 
Number. Height. Carbonate. Carbonate. 
800 850’ 65.05 34.77 
804 67.88 31.96 
811 61.79 37.96 
