CHAPTER XXIV. 



THE PLACER DEPOSITS. 



The North-Western Goldfields. — Compared with the other goldfields 

 of the colony the contour of the North- Western district is relatively 

 even ; the creeks and their tributaries are of low grade, and hence the 

 natural facilities for the economic treatment of placer gravels are not 

 equal to those in the more hilly districts. 



In the placers in the neighbourhood of Arakaka the gold-bearing 

 gravels are usually covered by from two and a half to four feet of a 

 heavy clay, ranging in colour from yellow to red, and which is frequently 

 underlain by bluish clay resting directly on the gravel. The gravels 

 are from two to two and a half feet in thickness, and carry approximately 

 one and a half to two pennyweights of gold per cubic yard. 



At the Manikuru Placers the gravels, as a rule, are covered by 

 yellow to reddish clay of very varying depth, usually ranging from 

 two to seven feet, but which, in places, are as much as fourteen feet in 

 depth. The gravels also vary greatly in thickness, from two to seven 

 feet, and are of about the same richness as those near Arakaka. The 

 Warimba Placers are of similar character to those on the Arakaka side 

 of the river. 



The constituents of the gravels are quartz in great predominance, 

 concretionary ironstone, and hei-e and there pebbles of more or less 

 altered basic rocks. In the upper parts of the creeks and of their 

 tributaries the ((uartz pebbles in the gravels are usualh^ coarse and 

 angular, and show no signs of having travelled far from their places of 

 origin. The quartz pebbles in the gravels of the lower reaches, and 

 the flats of the creeks and streams, are also more or less angular and, 

 as a rule, only slightly water worn. As the river is apprt»ached the 

 pebbles become more water-worn. 



In the higher placers the gold in the gravels is coarse and in many 

 places nuggety, while in the lower ones it is usually in line grains, 

 although fair-sized nuggets have been found in them. The largest 

 nugget found in these districts weighed about ten ounces. 



The placers in the higher parts of the Barima River, near the 

 Five Stars and Jimbo Creeks have given high ^^ields of gold. The 

 characters of the placer deposits resemble those of the lower districts, 

 but great boulders of epidiorite and of hornblende-schist occur in them. 

 The gold-bearing gravels on the average are about two and a half feet 

 in thickness. The gold found in them is usually coarse and nuggety. 



