530 
Prof. Licersidge — Chalk in New B ritain. 
microscope reveals the presence of the smaller Foraminifera, of a few 
sponge spicules, and minute grains of what are evidently siliceous and 
igneous rock. 
The further examination showed that the material is limestone, 
having a very close resemhlance to chalk, both in Chemical composition 
and in physical properties ; in colour it is not the dazzling white of 
some chalk, but bears a closer resemhlance to the light grey varieties. 
Although it is essentially composed of carbonate of lime, still it is 
not perfectly pure ; there are certain impurities present in the form of 
alumina, iron, silica, manganese, etc.; but reference will again he 
made to this question later on. 
To ascertain whether my supposition that the rock might he regarded 
as chalk and not merely as a soft, white friable recent limestone, or as 
a deposit such as is now forming over parts of the beds of the Atlantic 
and Pacific Oceans, I took an early opportunity, when writing, to 
inclose a portion of the material to Mr. H. B. Brady, F.K.S., of 
Newcastle-on-Tyne, who has devoted himself to the study of Foramini- 
ferous deposits, and I have since received a reply from him, in which 
he says : — 
“ First, let me speak of your chalk from the New Britain Group. I 
suppose you have ascertained that it is a Cretaceous chalk and not a 
friable Tertiary limestone. All the Foraminifera, or nearly so, are 
South Pacific recent pelagic and deep-sea species, Globigerina bulloides, 
Gl. inflata , Pulvinulina Menardii (a thick variety which I do not think 
is yet named), P. Micheliniana, and probably P. Karsteni, Pullenia 
spharoides, Nonionina umbilicatula, Bulimina Buchiana, fragments of 
Bentalina, Uvigerina, etc. Also a characteristic Pulvinulina, with 
thick shell and honeycombed surface, not yet described, of which I 
ha,ve quantities in the ‘ Challenger ’ material.” 
In answer to a question as to the locality and mode of occurrence of 
the material used for the carvings, the Rev. G. Brown wrote to me as 
follows : — “The chalk of which the figures are formed is, I am in- 
formed, only found on the beach after an earthquake, being cast up 
there in large pieces by the tidal wave. It is only found, as far as we 
know at present, in one district on the east side of New Ireland.” 
We have now to consider its Chemical composition in somewhat 
closer detail, and to compare the results furnished by analysis with 
those yielded by specimens of typical or true chalk. 
Chemical Composition of specimen from New Ireland. 
Hygroscopic moisture, i.e. water driven off at 100° C. ... 1-202 
Carbonic anhydride 
Iron sesquioxide . . . 
Alumina 
Silica 
Phosphoric acid ... 
Manganese protoxide 
Lime j. 
Magnesia 
Potash... 
Soda ... 
Chlorine 
Combined water and undetermined 
35-337 
1-597 
3-131 
7 933 
Minute trace 
•623 
45-278 
•476 
•308 
•260 
•105 
3 - 750 
Specific gravity, 2-199 at 59° F. 
100 000 
