Thp Orii/iii of the Placi'v Gold in, Guiana. 211 



is als(» the case with the coiicretioiiaiy ironstones, many of which are 

 barren, whilst others contain half an ouiice, or occasionally more, of 

 gold to the ton. Where auriferous miiieralised masses occur on the 

 hillsides or in the valleys their decomposition-products will naturally 

 be richer or poorer in gold according to the relative proportions of the 

 metal the masses contained. 



The gradual destruction b}^ sub-ferial detrition of the laterites on the 

 slopes of the hills has set free the quartz gravel, the finely divided gold 

 and the concretionary ironstones, and these, together with a good deal of 

 the laterite, have gi-adually travelled to the ravines on the hillsides and to 

 the lower parts of the valleys. The action of running water in the 

 ravines and valleys has gradually worn away the relatively soft con- 

 cretionary ironstones, and liberated the gold contained in them, the 

 metal accumulating in a Aery finely divided form in the resultant 

 valley gravels, where, in places, by sul^sequent solution and re-dep(tsition, 

 it has become aggregated into coarser particles and into nuggets of veiy 

 varying sizes. 



In certain districts fissure veins of quartz occur, which are more or 

 less auriferous, whilst, in places, great masses of auriferous quartz are 

 found, generally in hornbleudic or chloritic schists. As these were 

 exposed by denudation they gave rise, by detritive processes, to placer 

 gravels, some of which are very rich in gold. But this mode of 

 formation of aurifei"ous gravels is of very subordinate importance to 

 that of their derivation directly from the country rock in British 

 Guiana ; and, in my oj^inion, not 10 per cent, of the placer graAels 

 in the parts of the colony I have visited have originated from quartz 

 reefs and masses. 



In leaving the subject of the auriferous districts in British Guiana 

 and their deposits I cannot do better than quote Mr. Braddon's opinion 

 on them as given in the Minin<j Journal : — 



''The Guiana alluvial gold fields are possibly the richest existing 

 tti-day. . . . These goldtields are, further, amongst the most extensive of 

 the world. The payable lields already proved cover upwards of one thousand 

 square miles, whilst a great part of the Colony still remains unprospected. 

 The volume of worked ground, which can all be profitably re-worked bv 

 properly devised hydraulicking, is unimportant in lelation to that which 

 remains untouched, even on the established lields. 



" The gold-bearing so-called alluvia of Guiana have one very inqiortant 

 and special characteristic : they are not confined to the true alluvial drifts 

 of rivers and creeks, as in most countries, but embrace a very great extent 

 of enriched surface and payable decomposed country rock. 



" The possibilities of discovering valuable lode forms of deposits in the 

 process of hydraulicking off the surface residual matters are very real and 

 attractive. There are many other special natural advantages for mining in 

 Guiana against few natural disabilities. The Colony has the elements for 

 a very large development of hydraulic mining and dredging, which should 

 directly lead to the discovery and be accompanied by the opening of valu- 

 able lode, or lode forms, of deposits. For the successful prosecution of such 

 operations modei'ate capitalisations are wanted, with intelligent, experienced 

 honest and ])ractical direction, towards definite, clearly peiceived, well- 

 chosen, and steadfastly followed purposes. 



" The circumstances ai'e in every way favourable for the activities of 

 private enterprise from outside." 



