Geological Socieli/. 225 



Pulo Pinang, or Prince of Wales's Island, is stated to consist of a 

 central mountain range, with plains on the eastern and western sides. 

 The mountains are said to be composed wholly of granite, varying in 

 the siice and the proportion of the constituent mineralj and to be tra- 

 versed by veins of quartz and finely grained granite. The plains are 

 described as formed entirely of alluvial matter, in which no animal 

 remains have been found. The author conceives that these plains 

 have been gained from the sea, which, according to his opinion, once 

 washed the foot of the mountains. Stream tin, in small quantities, 

 is stated to occur near Amees Mills, but no veins of this mineral 

 have been found. The sea is said to be making considerable ravages 

 on some parts of the coast, but on others to be depositing extensive 

 mud banks. Of the neighbouring islands Pulo Rimau, Pulo Jerajah, 

 Pulo Ticoose, and Pigeon Island, consist of granite j Pulo Boonting, 

 of feltipathic rocks ; Pulo Sonsong, the Pulo Kras, Pulo Kundit, of 

 argillaceous schists ; Pulo Bidan, of limestone resting on argilla- 

 ceous schist J and Pulo Panghil, of limestone similar to that of the 

 island last mentioned. 



A paper was then read, entitled, "An attempt to bring under ge- 

 neral geological laws the relative position of metalliferous deposits, 

 with regard to the rock formations of which the crust of the earth is 

 formed," by M. Albert Louis Necker, For. Mem. G. S. &c. 



The author commences by remarking, that ancient writers failed 

 in their attempts to establish fixed rules for recognizing metalliferous 

 districts by the external configuration of the soil ; and that the laws 

 which guide the miner in discovering new metalliferous veins in one 

 country will often not assist him in another. He next observes that, 

 as far as he is aware, Werner and his disciples abandoned the idea of 

 establishing a connexion between formations and metalliferous depo- 

 sits ; and that Hutton considered the connexion of veins and the rocks 

 through which they pass to be purely fortuitous. He then states, 

 that he believes Dr. Bou^-* was the first to point out, in a general 

 manner, the relative position of metalliferous veins and primary un- 

 stratified formations ; and thus to lead to the inference, that the me- 

 tals were deposited in the former by sublimation from the latter : and 

 he adds, that Baron Humboldt f accounts for the association of the 

 mines of the Oural and Altai mountains with granite, porphyry, and 

 syenite, by supposing all of them to be the effect of yolcanic agency, 

 taken in its most extended signification. 



This doctrine, the sublimation of the metalliferous contents of veins 

 from igneous matter, the author states, occurred to him twelve years 

 ago, from observing the deposition of specular iron on the crust of a 

 stream of lava flowing down the side of Vesuvius ; and he was in- 

 duced from that circumstance to institute a series of inquiries, and in 

 further prosecution of the subject, he proposes in the memoir the fol- 

 lowing questions : — 



1st, Is there near each of the known metalliferous deposits any 

 unstratified rock ? 



* Miinoirc dcolofiique sur VAIleniaf'nc. 

 \ lissai lie (jco/dfiic rl fie (Timaloloi^le Asialique. 

 Third Series, Vol. 1 . No. 3. Sept. 1 832. 2 Ci 



