Tlie I'loxer Deposits. 



i03 



altered ([uartz-porphyiy and small pieces of sandstone. Towards the 

 higher parts of the valley the gravel is coarser, and consists of rough 

 angular ijuartz shingle, and fi-agnients of partially decomposed diabase 

 and quartz-pori^hyry. The average depth of the gravel is about three 

 and a half feet, and its yield of gold is aljout two jjennyweights to the 

 cubic yard. In this district the gold is always very fine. 



The placer gra%els on the Konawaruk River are somewhat shallow, 

 the average depth oi their cnerburden being about two feet. This 

 consists of yellowish cla}^, and is underlain by about three and a half 

 feet of greyish-brown, very angular quartz gravel. The gravel yields 

 on the average about one and a half pennyweights of somewhat coarse 

 gt)ld per cubic yard of the pay-dirt. 



The foregoing brief descriptions of some of the mijre important 

 placer gravels in the colony show that in few, if any, cases has the 

 gold-bearing gravel tra^■elled far from its place of (jrigin. The fact that 

 in the great majority of the gravels quartz showing gold other than 

 " paint " gold is of somewhat rare occurrence, indicates that the source 

 (»f the gold in the placer gravels ought not to Ije sought for in quartz 

 reefs, but in the country rock. There are, of course, exceptions to this 

 general rule, as in parts of the Puruni District and in some of the 

 ravines in the Arakaka District, where the gold has been derived in 

 part, at least, from auriferous quartz reefs and masses. 



Till' Placi'i' Gold. — The quality of the gold obtained from the VcXrious 

 districts varies to some extent, as is indicated by the following: — 



Placer Gold from 

 Konawaruk 

 Mahdia, Potaro 

 Groete Creek 

 Barima 

 Cuyuni 

 Puruni 

 (hiiai. Essequibo 



Fineness. 

 <S91 

 911 

 911 

 912 

 926 

 9:55 

 941 



