DISTRIBUTION OF MINERALS IN SARAWAK 17 



Nuggets are of extremely rare occurrence and I have never 

 seen one of any size, but if the Chinese are to be credited, some 

 of very considerable weight have been met with in the adjacent 

 Sambas District. St. John mentions having seen one of 7 oz., 

 taken from the auriferous clay at Krian near Bau, and this is 

 the largest which I have heard reported on credible authority 

 to have been found in Sarawak. The gold dust is usually in a 

 state of the finest comminution, but I have seen samples from 

 Kumpang, near Marup, composed of fine dust intermixed abun- 

 dantly with thin flat plates of the metal of from i to X V inch dia- 

 meter — a form which has been ascribed to some original laminated 

 structure in the present matrix. I am informed that similar plates 

 have been detected in the siliceous veinstones of the antimony 

 lodes ; but where I have had the opportunity of seeing the gold 

 in these veinstones it appeared in very minute sparsely scattered 

 specks without a sign of running into plates or veins. The 

 veinstones are now and again found to contain a very profitable 

 percentage, according to the estimate of the Chinese, who quarry 

 the stone in a superficial way, and pounds it in wooden mortars 

 with iron rammers. One block of siliceous manrix (about 15IBs.) 

 at Paku containing some 20 per cent of grey antimony, when 

 thus crushed yielded about $12 worth of gold, but this result was 

 quite exceptional. At Jibong both the white quartz and the 

 black amorphous siliceous veinstones are crushed, and of these 

 two the latter is considered to yield the higher percentage of 

 metal. Both in crushing the stone and in washing the alluvial 

 clays and gravels the find is very uncertain, and good "hauls" 

 seem few and far between. Marup, Bau, and Paku have afford- 

 ed remunerative washings, and Sirin in a less degree. The suc- 

 cession of the superficial deposits in the last locality are as 

 follows : — 



1. Vegetable mould. 



2. Unstratified Felspathic clav. 



3. Clayey Gravel. 



4. Uptilted indurated clay-shales. 



The whole section to the basement-rock of clay is only 5 or 6 

 feet in thickness, and it is in the stratum of gravel that the gold 

 is found, associated with small rolled fragments of cinnabar and 

 the clay-ironstone which abounds all over the gold and antimony 

 districts of Sarawak. The components of the auriferous gravel 

 are granite, quartz, sandstone, impure-agate, porphyrite, &c. 

 The surrounding country is made up of steep low hills of indu- 

 rated clay-shales and clayey sandstone with yellow felspathir 

 clay overlying, and is seamed with dykes of hornblendic trap- 

 rocks ; and a short distance to the S. and W. limestone hills 

 appear. 



