ORIGIN OF GOLD NUGGETS. SLE 
ous, many large nuggets have been found remote from basaltic 
areas, and Mr. Birkmyre’s list shows that the fields most remote 
from basaltic areas have produced the most large nuggets; in 
Gippsland if not large they are numerous. 
Mr. G. Attwood in a paper on Gold from Guayra, Venezuela, 
S. America—(Journ. Chem. Soc. London, 1879, p. 427-9), con- 
cludes, from an examination of one particular specimen, that gold 
nuggets do gradually increase in size owing to the accumulation 
of fresh particles of finely precipitated gold. 
Prof. Whitney, in. a paper—TZhe Auriferous Gravels of the 
Sierra Nevada of California, Cambridge, U.S.A., 1880.—says 
that “it does appear as if there was some truth in the idea that 
the finding of large pieces of gold in the gravel is not justified by 
what we see of the occurrence of the metal in the quartz. It is 
certain, at all events, that the form of the ordinary nugget is 
something different from that which is offered by the gold as 
originally deposited. In quartz it is either quite invisible or else 
it is scaly, foliated, filamentous, arborescent, or crystalline, quite 
unlike the rounded and smooth or flattened pieces met with in 
alluvial deposits.” He, however, points out that this difference 
could be produced by attrition, and he thinks it highly improb- 
able that masses of gold in gravel could be enlarged by any 
chemical influence. 
The bark of some of the tree trunks found buried in the blue 
gravel (Cal.) is largely replaced by iron pyrites and this is rich in 
gold, ‘hence we cannot deny that some gold has been deposited 
in the placers from solution, but this certainly does not include 
the nuggets and gold dust.” He also says, “‘if the gold of placers 
were deposited from solution, we should necessarily find much of it 
crystallized and forming strings and sheets running through the 
porous material; whereas, as a matter of fact, crystals are never 
found in placer gold, nor are sheets or threads. Scales, grains, 
pebble-like nodules, round battered masses, these are what we 
find.” 
