92 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
increased to 27.7, while at 610 feet no less than 42.7 per cent of mag- 
nesium carbonate is found. At this point the section of the older rocks 
is masked by terraces or fringing reefs, which form a cloak of newer 
material, only pierced at one point above sea-level, where an Eocene or 
Oligocene limestone occurs (No. 635) having 3.9 per cent of magnesium 
carbonate. - 
F Calci M i SOUTH-EAST 
Number.) Height. | carbonate. | Carbonate. OF PHOSPHATE HILL 
610 97.0 30 OLvER Rocks. 
611 97.3 2.7 
96.8 3.2 
790 
97.1 2.9 
97.7 2.3 700 
72.3 27.7 
57.3 42.7 
96.1 3.9 
D 
ZL 
610 
Microscopical. No. 610. — A limestone containing an unrolled frag- 
ment of Orbitoides, together with Polytrema, Amphistegina, and a little 
yellow isotropic material, possibly palagonite. The organisms are well 
preserved, the rock is cavernous, and the semi-opaque matrix is seen 
under the high power to be crystalline. 
No. 615. <A very cavernous dolomite showing no traces of organisms, 
except a few meandrine forms. The spaces and cavities in the rock 
have been, to a great extent, filled with large slightly yellow crystals 
of secondary calcite. 
No. 616. A uniform, compact, fine-grained dolomite, showing a few 
small fragments of Lithothamnion, and here and there dark meandrine 
patches suggesting the former presence of Polytrema. 
SypneEy’s Datz. — This dale is a gorge on the west coast, originally 
determined by a fault line, and further excavated by a stream which 
runs through it, In this dale Oligocene or Eocene beds occur, con- 
taining the oldest type of Orbitoides met with at Flying Fish Cove. 
Chemical. — Three limestones were analyzed: No. 308, from a height 
of 350 feet, contains 39.22 per cent of magnesium carbonate, while No. 
