282 TlMEHRL 
There are grounds for believing that diamond mining 
may become in the future an important industry in 
British Guiana. It is a comparatively common occur- 
rence to find diamonds in the gravels of our placers, and 
about two years ago some excitement was created by 
the discovery of the gem on a somewhat extensive scale 
on the Upper Massaruni. Upwards of eight hundred 
gems were obtained in a short time, and although they 
were all of small size and of little value as ornamental 
stones, the discovery is important as shewing the possi- 
bility of valuable diamond fields existing. 
Nothing is known with certainty as to the origin or for- 
mation of the diamond in nature, although the experiments 
of Mr. HANNAY of Glasgow in producing crystallised car- 
bon artificially, favour the general idea that it has resulted 
from the slow decomposition of certain gaseous hydro- 
carbons ; but the fa6l is clearly established however that 
it is to be sought for chiefly in very recent formations. 
Sir R. BURTON after a careful study of the Brazilian 
fields was led to form the opinion that the diamond is 
evidently " younger at times than the formation of gold, 
and possibly is still forming and with capacity for growth," 
a conclusion which derives support from the position in 
which it is so often found in the arenaceous and alluvial 
matters, such as strata of iron-shot sand and clay that 
accompany the tertiary and quarternary epochs. The 
celebrated traveller JOHN Ma WE states that the sub- 
stances accompanying diamonds and considered good 
indications of them are bright bean-like iron-ore, a 
slaty flint like substance approaching Lydian stone of 
fine texture, black oxide of iron in great quantities, 
rounded bits of blue quartz, yellow crystals etc. 
