124 EAMBLES OF A NATUEALIST. [Oh. YIH. 



characterised the neighbouring Craig Island. Agincourt was 

 covered more or less with vegetation; but there were no 

 trees, and only a poor apology for shrubs. The sea in the 

 immediate ^neighbourhood of this group has a general depth 

 of rather more than 100 fathoms. 



About 75 miles to the E.N.E. of Agincourt is the second 

 group of islands, consisting of Hoa-pin-san, Tia-usu, and 

 the Pinnacle Eocks, the last consisting of several distinct 

 islets, and formiag, with Hoa-pin-san, one group. Hoa- 

 pin-san is composed of trappean rocks, with a bold outline, 

 and rising nearly 1200 feet above the sea ; while the Pin- 

 nacle Eocks well deserve their name, from the remarkable 

 forms which the most elevated and prominent of them 

 assume, and which look like buildings, lighthouses, &c. I 

 did not approach them near enough to ascertain their struc- 

 ture ; but Sir Edward Belcher * says, with great probability, 

 that they are masses of grey columnar basalt, upheaved and 

 subsequently ruptured, and rising suddenly into needle- 

 shaped pinnacles, which are apparently ready for disintegra- 

 tion by the first disturbing cause, either gales of wind or 

 earthquakes. Tia-usu also is composed of huge boulders of 

 a greenish porphyritic stone, probably a basalt, cemented by 

 coralline and amygdaloidal matter. 



On none of the islands of this group are there any trees 

 or shrubs — they have a rocky and desolate appearance, only 

 relieved by the multitude of birds which darkened the waters 

 around by their vast flocks, as they sought their resting- 

 places towards sunset. The islands, too, are more or less 

 whitened by their deposits. The soundings around this 

 group reach 80 fathoms. 



In the night we sighted at eight miles distance a rock, 

 • Voyage of the Saiuarang, vol. i. near the end. 



