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GEOLOGY OF PULO PINANG, 



structure, and splits into tables when struck with the hammer. The 

 veins vary from half an inch to one and a half inch in thickness, and 

 the quartz in them seems to be broken in pieces, between which is observed 

 a metallic(?) crust, (Nos. 32 and 33). The beach is stony and clayey, 

 different from that of the granite island, which we invariably found either 

 rocky, sandy or gravelly. At low water mark, the quartz veins form a 

 curious cancellated appearance. The softer rock between them having 

 been destroyed by the action of the water, they rise in sharp lines 

 considerably above the level of the clay, and are, in some places, scarcely 

 passable without danger of having the feet cut or bruised. Beds and 

 rolled masses of iron-stone were seen along the coast, near the north-west 

 corner more especially ; the former dipping at an angle of about 52°. 

 The rolled masses are of considerable size, some being twelve or fourteen 

 feet high, and as many in breadth, looking, at first sight, like volcanic 

 rocks, from their burnt and cancellated appearance. They are formed 

 of a kind of jaspery iron-ore, containing numerous drusy cavities, 

 coated with semi-globular crusts of chalcedony and yellow ochre, some of 

 the specimens of which are very beautiful, (No. 34). The specific 

 gravity of it is 3.000. It strongly resembles, in all its characters, the 

 mineral substance described and figured by Mr. Sowerby, in the 

 5th volume of his British Mineralogy, page 173. tab. 494, under the 

 name of " Burnt rock." No. 35 represents another ore of iron, of specific 

 gravity 3.640, found also in rolled masses on the coast, from which that 

 valuable metal might be obtained in abundance. In some places, by the 

 action of the water, the softer iron-stone has been converted into a fine 

 yellow ochre, which might be used in painting. The whole of the west 

 side of north Pulo Kra is ratlier bold and rocky, in some places even 

 precipitous ; and here and there are deep caves. Along the shore are 

 found numerous sea slugs, or Holothurice, and the beautifully polished 

 and variegated Cyprcea shell, besides coral and sponges of various kinds. 



