ASSAM GOLD. 91 



The authors were unable to trace the original rock containing the 

 gold in situ. Various kinds of granite, in the form of boulders, accompanied 

 by gneiss and greenstone, occurred at the Brahmakoond. Felspathic rocks 

 and slates are in aitu. The granite and gneiss boidders frequently 

 contain pyrites, and are accompanied by magnetic iron sand in large 

 quantity. Much quartz, consisting of pure white quartz, (vein-quartz ?) 

 ferruginous quartz, and cellular quartz was also found. 



The spots selected by the native gold-washers are those salient 

 angles or reaches of the river, where the alluvial deposits, cut away by 

 the stream from the opposite bank, are partially re-deposited, after having 

 undergone the sifting action of the current. The highest point in the river, 

 at which the natives work, is Dora-Mookh, a few miles below Parghat. 



At a point 4 miles up the Dora stream, where it issues from the 

 hills, a thick deposit of pure Kaolin was found resting on white quartz, 

 and probably brought down and deposited by the river. It is termed 

 by the natives rooJcmani-pitha. 



At Gooroo Mora, 18 miles below the Brahmakoond, the yield of gold, 

 from 70 maunds (2^ tons) of gravel, washed in a Callforniau cradle, 

 worked by four men, was 30 grains, valued at 2 Rupees 8 annas. In the 

 native trough (or Dooruni), worked by three men, the yield from 25 

 maunds (18 cwfc.) of gravel, Avashed in one day, was about 12 grains, 

 worth one Rupee. This was not considered by the natives as a good 

 yield, and they stated that, after a heavy flood, they can sometimes 

 obtain about double that amount from, the same quantity of gravel. 



The Digaroo Tributary, which comes from the hills to the Northward, 

 and brings down large boulders of crystalline limestone, granite, gneiss, 

 serpentine, and quartz, was also searched for gold, but unsuccessfully, 

 except within about 5 miles of its junction with the Brahmapootra, or 

 about7miles from the hills; and here gold only occurred in small quantities. 



The Noa-Dehing, a large tributary from the South, was also examined 

 with similar results. The gold was accompanied by platina and mag- 



