ORIGIN OF GOLD NUGGETS. ey! 
3. It is urged that if nuggets had been derived from veins that 
their forms would be different, and especially that they would 
retain traces of crystalline form and roughness within the cavities, 
and would not possess mammillated surfaces. 
As I have pointed out in another paper, (On the Condition of 
Gold in Quartz Veins, p. 301) it is very unusual to find any trace of 
crystalline structure in the gold set free from veins. Roughness 
of course, we do meet with in vein gold, but when the gold 
weathers out from the reef this is gradually lost by abrasion; the 
projecting points of soft malleable gold are flattened down and 
rounded off rather than ground away in powder, as in the case of 
hard and brittle substances, and the nuggets would necessarily 
acquire a mammillated appearance. 
It is quite true thac heavy nuggets would not be so easily 
carried by currents as ordinary pebbles and boulders, still they 
would be moved and rolled occasionally, by masses of rock forced 
against them, also by being undermined and falling over; further, 
although perhaps not moving much themselves, they would be 
subjected to nearly as much abrasion by the constant attrition 
of other and lighter pebbles grinding over them. The cavities 
in such nuggets would also be smoothed off and rounded out by 
the constant stream of water-borne sand and pebbles searching 
every crevice, acting much like the sand blast, but less quickly; 
as the nugget fell over from time to time all parts of its surface 
would be abraded in turn. 
To bring this about, I do not think it is necessary to assume 
with Sir Roderick Murchison and Prof. Egleston, that the violence 
of the old currents was greater than that of those of the present 
day; when in flood, streains of the present day are quite powerful 
enough to shift, in the manner described, the largest nugget which 
has yet been found; even in their normal condition existing streams 
would eventually bring about the form and general appearance 
possessed by nuggets. 
4. It is stated that large nuggets are much more common than 
large masses of gold in veins. As I have already shown, large 
