98 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Chemical. — Four analyses were made, and the rocks were found to be © 
limestones, containing only a minute quantity of insoluble material, and 
from 2.6 to 5.8 per cent of magnesium carbonate. 
Calcium Magnesium Insoluble 
Number. Height. Carbonate. Carbonate. Residue. 
354 500/ 94.3 5.7 024 
374 500’ 94.2 5.8 
304 470° 95.5 4.5 024 
368 440’ 97.4 2.6 
NortH-£ast Port, — A specimen from the summit, at height of 600 
feet, yielded 1.72 per cent of magnesium carbonate, and .2 per cent of 
calcium phosphate. 
Calcium Magnesium Calcium 
Number. Height. Carbonate. Carbonate. Phosphate. 
179 600’ 91.72 1.72 .20 
Microscopical. — A limestone, with a matrix largely of silt, containing 
unaltered Lithothamnion, Carpenteria, Polytrema, Truncatulina, and 
Amphistegina. Cracks in the rock have been filled with a mosaic of 
secondary calcite, while some cavities are lined with scalenohedral 
crystals. 
First Inland Clif (Newer fringing Reef. Late Pliocene ?). 
Norra or Frying Fish Cove.— At Flying Fish Cove the fringing 
reefs are not represented, but a little to the north the shore cliff is 
found, and also the first inland cliff, which forms a well-marked feature 
between the heights of about 60 and 300 feet. . 
Chemical. — All the rocks analyzed from this cliff are limestones, but 
at levels of 250 feet (No. 211), 200 feet (No. 208), and 50-60 feet 
(No. 200) the amount of magnesium carbonate present rises to 10.9, 
8.5, and 10.5 per cent respectively. In the remaining limestones the 
amount varies from 2 to 4 per cent. 
Microscopical. No, 1082. — A rock composed of fragments from the 
reef. Calcareous alge, Polytrema, and echinid spines occur, but a large 
part of the slide is oceupied by a section of a compound coral, whose 
organic structure is well preserved. Crystals of aragonite are in opti- 
cal continuity with the coral fibers, and wholly or partly fill the inter- 
stices. The residual space is filled with a clear mosaic of calcite, which 
looks as if it has arisen largely at the expense of the aragonite. In 
some parts of the slide organic fragments are invested with a coating of 
fibrous calcite crystals. Some of the organisms are represented only by 
