418 PROCEEDINGS OF SECTION C. 
for 1883.* Hence it was considered unnecessary to further 
examine these specimens from Florida Island. 
7. Chalk from Ulawa Island, together with flints set free from 
the same.—Both the chalk and the flints closely resemble those of 
the south coast of England ; the chalk also closely resembles that 
from New Ireland, (See ‘““On the Occurrence of Chalk in the 
New Britain Group,” by A. Liversidge, Jour. Roy. Soc. of 
N.S. W., 1877) ; except that in the particular specimens of the 
Ulawa chalk examined by me, foraminifera are not so abundant 
as in the New Ireland chalk, nor are there very many sponge 
spicules. 
The specimens are all rolled, and could not by mere inspection 
be distinguished from those found at the base of the English 
chalk cliffs. 
T did not consider it necessary to make a complete analysis, 
but the amount of calcium carbonate and soluble matter was 
determined and found to be 93°66 per cent., hence in composition 
the rock is essentially a chalk; the insoluble residue, 6°33 per 
cent. is gelatinous, of a pale brownish colour, and is composed of 
particles of silica and the usual rock deérvis. The differences, 
between a chalk and a limestone are, apart from geological age 
mainly physical. 
8. Flints set free from the above chalk, Ulawa Island.— 
Some of the flints are not distinguishable in appearance from 
English chalk flints, but others are rather more chalcedonice. 
In all, there were ten specimens of flint, and the specific 
gravities of four were determined. 
1. A brown chalcedonie flint, more or less translucent and 
with a well marked conchoidal fracture, had a sp. gr 
of 2:21 to 2°22. 
A dark smoky flint with whitish spots and markings, 
and outer skin or crust, so common on chalk flints, 
well marked conchoidal fracture. The whitish coating 
varies from ;), in. to in. thickness. The sp. gr. of 
two pieces were found to be 2°39 and 2°36. 
to 
(Se) 
. A pale brown chalcedonie flint with white films running 
through it, fissured ; well marked conchoidal fracture, 
but breaks into small pieces on account of the 
numerous fissures. The sp. gr. was found in different 
pieces to be 2°23, 2:24, and 2:23. 
4. A greyish-coloured flint, with a platy or laminated 
structure. The fissures between the larger plates 
little chalk. The sp. grs. of three pieces were found 
to be 2:15, and a porous specimen 2°23. 
* On the Composition of Some Coral Limestone from the South Sea Islands,” by A. Liver- 
sidge.—Jour. Roy. Soc. of N.S.W., 1880. 
