ANNIVERSARY ADDRESS. 33 



Associated with the preceding formation there occurs a very 

 siliceous schistose limestone, in twisted and contorted very thick 

 beds which have been much denuded, so that they form isolated, 

 elevated, cavernous, and fantastic masses, sometimes of striking 

 character. These beds extend for fifteen miles between Hien- 

 guene and Touo. 



There is also an old limestone interbedded with the fusible 

 slates which are met with in the centre of the island behind 

 ITouagape, along the river Ti-Houaka towards Poimbey. 



Owing to the absence of fossils, all that can be said for these 

 rocks is that they are ancient, and are considered by Mons. 

 Garnier to be either Silurian or Cambrian. It is in the Mica- 

 schists of the oldest of the above formations, that gold was found 

 about Poebo, in 1863, but in 1864, when Garnier passed that 

 way he found only one digger steadily at work, who after- 

 wards abandoned it. Since then, further trials have been made 

 by English adventurers and others, and if the statements of 

 reporters are conclusive the eventual amount will not be very 

 considerable. As this opinion was given in 1867, perhaps it was 

 too decisive, and hereafter, when the reefs shall have been 

 crushed a larger product may be realized. 



The description of the Gold-field may be worth giving. It was 

 situated about two miles frem Poebo. The bed rock is a garneti- 

 ferous micaschist, which is covered by a red clay resulting from 

 the decomposition of ferriferous garnets • the rock sometimes 

 takes a spheroidal form, and in the centre of the spheres the 

 garnet is less abundant and is replaced by a quartzose and 

 pyritous matter, the masses themselves being extremely hard and 

 surrounded by the soft argillaceous products of decomposition. 

 They are often covered with a bed of mammillated oxide of 

 Manganese. That the gold comes from the rock in situ was 

 shown by the greater abundance of it in the sands nearest the 

 rock in the dry bed of a river which traversed the deposit of 

 clay. 



A supposed Devonian formation occurs next in succession to 

 the older rocks just mentioned, and is exhibited not far from 

 c 



