

CALCAREOUS FORMATIONS OF THE SOLOMON GROUP. 567 



from its mouth one of these streams, in cutting across the extremity of an out- 

 lying spur of the neighbouring hills, exposed a soft earthy rock bedded with a 

 gentle inclination of 2° to 3°, and abounding with organic remains. This rock 

 resembles the prevailing formation of Alu, the principal island of the adjacent 

 Shortland Islands already described. Further up the stream, the same deposit 

 was exposed in the banks, until I reached a narrow gorge rather over a mile 

 direct from the coast, the sides of which were of a chalky coral limestone. 

 This limestone I traced up the slopes of an adjoining cluster of hills to an 

 elevation of about 120 feet above the sea. A grained limestone* then 

 appeared at the surface, and composed the summit of the hill, which was 

 elevated about 200 feet above the sea. 



Subsequently I ascended another stream which opened into the bay. After 

 following its course through the mangrove belt for about two-thirds of a mile, 

 I struck off on foot through the swamp, and came upon a mound about 35 feet 

 high — an outlier of the neighbouring hills — which rose up like an island from 

 the midst of the swamp, and was formed of the same deposit, similarly laden 

 with organic remains, as that which I had observed during my ascent of the 

 neighbouring stream. Ascending one of the outlying hills to a height of about 

 a hundred feet above the sea, I found the same deposit, but not sufficiently 

 exposed, however, to display bedding. 



Unfortunately the uncertain reputation of the natives restricted my field of 

 observation. I was, however, able to satisfy myself that the mass of the low- 

 lying land near the coast was of this soft earthy deposit, the characters of 

 which will be now described. 



When in the mass, it has the appearance of an argillaceous earthy rock, 

 somewhat moist and effervescing with an acid ; and displaying to the eye 

 numerous Pteropod shells of the genera Hyalcea, Diacria, &c, Lamellibranchiate 

 and Gasteropod shells, the tubes of Dentalium being especially noticeable ; 

 otoliths of fish; macroscopic tests of such Foraminifera as Cristettaria 

 cultrata, Nodosaria soluta, &c, together with numbers of shells of the more 

 microscopic kinds ; and, lastly, often fragments of leaves. Subjoined is the 

 description given by Mr Murray of samples of this deposit : — 



A very friable rock, of a greenish-grey colour, having the composition of a 

 Foraminiferous ooze mixed with much volcanic debris (it resembles the Short- 

 land deposits in all its characters). 



Carbonate of Calcium (3314 per cent.) consists of otoliths offish, Pteropod 

 and Heteropod shells, Gasteropod and Lamellibranchiate shells ; Serpula 

 tubes, Ostracode valves, Echinoderm fragments, with many pelagic and 

 bottom-living Foraminifera {vide List). 



* This grained limestone has not been examined by Mr Murray. It, however, closely resembles 

 in appearance the Foraminiferal limestones of Alu, and is probably of the same character. 



