72 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
125 feet. — Color white with brownish white portions. The sample is of an 
almost pure white rock, but it contains a fragment of limestone like the pre- 
ceding, cracks in which have been filled with secondary calcite. It is a very 
porous rock for the most part. There are a few casts (or imprints) of parts of 
corals present. Consists of fragments of shells (lamellibranchs) and many 
ovules in a matrix of amorphous or unrecognizable material. Sometimes the 
shells have leached out leaving the rock porous. Part of the sample is a true 
oblite, some of which is friable and some has been cemented by calcite to form 
а firm rock, The sample contains internal casts of lamellibranchs and frag- 
ments of their shells. A very small amount of limpid quartz sand is present. 
150 feet. — Color yellowish white. A trace of quartz sand is left on dissolv- 
ing the rock in HCl. Тһе rock seems to have been a hard, compact limestone. 
Observed fragments of shells and internal casts of lamellibranchs and a few 
pieces of coral ; many rounded grains, but very little true oólite. Most of the 
recognizable organic remains are of lamellibranchs. There are many facetted 
fragments which seem not to have been made by the drill, but to be the remains 
of the internal pillars of sea-urchin tests. There are many angular bits of stone 
which is as dense and crystalline as marble. 
175 feet. — Color white, A limestone like the last, except that it seems as 
if a larger proportion of it were porous and a smaller proportion determinable. 
A small amount of quartz sand is present. Lamellibranchs predominate among 
the remains that are determinable. 
200 feet. — Color yellowish with many pure white particles (bleached organ- 
isms). This sample consists almost entirely of a fine uncompacted calcareous 
sand in which there is a very small amount of limpid quartz sand. The par- 
ticles of the sand have been weakly cemented in places. А few chips indicate 
the presence of some compact rock. The grains are rounded and subangular. 
Ovules were noted but are scaree. Тһе fragments were almost all undeter- 
minable, but in the small portion of the sample which failed to pass through a 
No. 40 mesh sieve there were a few pieces of madrepore corals, some indica- 
tions of echini, fragments of both branching and inerusting bryozoa, bits of 
lamellibranch shells, and casts of minute gastropods. 
225 feet. — Color white with very slight yellowish tinge. Sample contains 
a small amount of fine angular quartz sand; coarser grains of quarts were 
rounded. Rock was a rather porous limestone with areas of granular calcite. 
Partly odlitic. There were but few determinable organic remains in the sam- 
ple. <A very few bits of coral, spines of echini, and fragments of ‘branching 
bryozoa were noted. Many fragments of lamellibranch shells and casts (Arca ? 
Pecten ? etc.), and a very few internal casts of minute gastropods. 
250 feet. — Color white. Sample consists of rounded and subangular grains. 
Rock was a soft, porous, and granular limestone. A considerable percentage 
of very fine-grained limpid quartz sand is present, the particles of which are 
angular or but slightly rounded. No definitely terminated crystals were ob- 
served, though some of the surfaces suggested the rhombohedral planes in shape ` 
and position. By far the largest part of this quartz sand is very minute in size, 
