268 TlMEHRI. 
evidence of any general and widespread distribution of 
gold-bearing drift, due to the breaking up of quartz 
veins and their enclosing rocks, as is to be observed in 
other places; such auriferous deposits as we find are 
apparently derived from the local decomposition and 
erosion of veins in situ. This would account for the 
patchy and irregular character of the deposits, as they 
are evidently formed only in the vicinity of existing quartz 
veins, and this may be considered as conclusive of their 
origin when it is found that in many of the streams the 
bottom layer of drift contains no gold, the metal being 
confined to the upper portion and the surface, proving 
that the deposition of the gold has been a very recent 
occurrence, and is still going on. While this militates 
against the district as a field for alluvial workings, it yet 
points the strongest argument in favour of its being a 
promising one for quartz-mining, and the very common 
occurrence of rich gold-bearing quartz in the wash-dirt 
tends strongly to confirm this opinion. The preceding 
remarks apply equally to the Demerara and the Upper 
Massaruni Rivers, where similar conditions are very 
noticeable. 
The rocks of the North-west belong mainly to the 
metamorphic series, and consist of quartzites, various 
schists, talc, chlorite etc., in association with gneiss, 
penetrated in parts by intrusive igneous rocks, and it 
may be remarked that in the best paying districts granite 
is never very far off. 
Over this district: there is a marked want of confor- 
mity with most of, the other gold-fields, in the absence of 
a peculiar formation usually described as composed of 
hydrated oxide of iron, which in the form of massive 
