CALCAREOUS FORMATIONS OF THE SOLOMON GROUP. 



563 



Uvigerina pygniaea (rare). 



Nodosaria hispida (few). 

 ,, papillosa ,, 

 „ raphanus ,, 

 ., filiformis (rare). 



Sagrina virgula (common). 



,, columellaris (very common). 



Lagena hispida (few). 

 ,, desmophora (few). 



Globigerina bulloides (common). 

 ,, ,, var. triloba „ 

 ,, conglobata ,, 



„ dubia „ 



„ sacculifera ,, 



„ rubra (many). 



Globigerina sequilateralis (many). 



„ inflata (few). 



,, orbulina (universa) (many). 



Sphasroidina dehiscens (many). 

 Ramulina globulifera (rare). 

 Truncatulina praecincta (few). 



„ lobafcula ,, 



,, haidingerii „ 



Pulvinulina menardii (common). 



,, „ var. tumida „ 



,, elegans (few). 



„ micheliniana ,, 



,, procera „ 



Pullenia obliquiloculata (few). 



„ sphseroides ,, 



The Coral Limestone. — This rock is found capping the inland ridges (as 

 shown in the section) where it does not attain a greater thickness than 30 to 40 

 feet, being usually much less. It displays considerable variety in its characters ; 

 and had I not satisfied myself of its true relation to the underlying soft deposit 

 previously described, I should hesitate in coming to the conclusion that all the 

 varieties belonged to an ancient barrier-reef. By striking the inland ridge 

 (marked A in the section) where it approaches the coast and following along 

 its crest for some three or four miles, one first finds capping the ridge and 

 overlying the soft deposit a hard compact yellowish-white coral limestone con- 

 taining many Amphisteginw. Further along, as the ridge gradually rises from 

 150 to 200 feet above the sea, this coral rock displays itself as a chalky lime- 

 stone capping the ridge and exposed in huge masses, with vertical faces 30 to 

 40 feet high, on its slopes. These large masses resembled much in their position 

 and appearance ancient reefs still occupying the sites they originally held 

 beneath the sea. The superficial position of this chalky coral limestone and its 

 relation to the underlying soft Foraminiferous deposit are points of some 

 interest.* Appended is the description given by Mr Murray : — 



A compact chalk-like coral limestone of a cream colour, showing no 

 definite structure, and resembling in section the Lower Chalk of Kent, if the 

 corals are not taken into consideration. 



Carbonate of Calcium (9576 per cent.) consists of Lamellibranchiate shells, 

 Polyzoa, Echinoderm fragments, corals, calcareous Algse, and Foraminifera 

 as Nummulina. 



* I found a similar chalk-like coral rock in the small island of Biu which lies off the north end of 

 Ugi Island. This island is only 11 miles in length and about a hundred feet in height in its centre 

 where this rock was found. It may be briefly described as a patch of coral reef which has been elevated 

 about a hundred feet. In the southern island of the Three Sisters, which are adjacent to Biu, I 

 obtained from the elevated central portion hand-specimens of coral rock which were in part chalky. 

 This island, like Biu, is simply a patch of coral reef which has been upheaved 60 or 70 feet above the 

 sea. The present reefs which skirt the more elevated portion have a rude atoll form. 



