152 J. J. S. Teal! ^ E. T. Neivton — Rocks from Tonga Islands. 



diameter) which, on comparison with examples of Orhulina universa, 

 kindly lent by Dr. G. J. Hinde, leave no doubt as to their 

 belonging to that species. 



The shells of the foraminifera are now represented by a colourless 

 isotropic substance, presumably silica, the whole of the carbonate of 

 lime having been removed. 



No. IV. From the centre of Telekitonga Island, one of the Otu 

 Tolu group, rounded lumps of pumice, which float in water, were 

 collected at about 10 feet above high-water. These are composed of 

 crystals of hypersthene, augite, and felspar in a highly vesicular, 

 nearly colourless glass. This is the type of rock so widely 

 distributed throughout the Pacific region. 



No. V (F. 313). This is a rather coarse and partly indurated 

 " coral sand " from Lalona Island, another of the Otu Tolu group ; it 

 is said to be a few feet above high-water, and a similar rock occurs 

 round the shore-line of all four of the islands forming this group. 

 It is a fairly hard rock containing rolled fragments of corals, 

 nullipores, and shells of small molluscs. A few examples of the 

 large stellate foraminifer, Tinoporus hacnlatus, may be seen. This 

 Ehizopod is common in the South Pacific, and occurs in some 

 abundance in No. VIII specimen. Professor Sollas found that 

 Tinoporus and OrhitoUtes form the greater part of the " sand " 

 which fills many of the interstices of the coral reef at Funafuti (see 

 Nature, Feb. 18, 1897). 



No VI is a pumice of hypersthene andesite similar to No. IV, 

 from the middle of this island of Lalona, at about 10 feet above 

 high-water. 



No. VII (F. 314). A consolidated "coral sand" similar to, but 

 finer than. No. V, from the eastern side of Lifuka Island, one of the 

 Haapai group, just above high-water. Rolled fragments of corals, 

 nullipores, etc., make up the mass of this rock, which, however, is 

 remarkable for the great number of the foraminifer, Tinoporus 

 baculatus, it contains, accompanied by the very similar, but spineless 

 form known as Gypsina. 



No. VIII (F. 315). Dark-brown sandy tuff, composed of andesitic 

 lapilli and broken crystals of hypersthene, augite, and felspar, from 

 Mo'unga'one Island, Haapai group, 30 feet above high-water. 



No. IX is from the same island, but at the coast-line and from 

 rocks 12 feet high. This is a cavernous mass of " coral rock," very 

 dense and much weathered, consisting almost entirely of indurated 

 coral, and may well have formed part of a coral reef. If the mass 

 of the rock is similar to this specimen, it is probable that it is an 

 elevated coral reef. 



No. X (F. 316) is a portion of the beach rock of Lofanga, 

 another of the Haapai Islands, and is said to have dead corals still 

 adhering to it. This, again, would seem to indicate an elevation of 

 the shore. The rock is an andesitic tuff; both lapilli and crystals 

 are surrounded by a thin incrustation of calcite, which acts as 

 cement and serves to bind the particles together. 



It is interesting to note that even in so small a series of specimens 



