ECONOMIC GEOLOGY. 63 
SOURCE OF THE GOLD. 
A large part of the gold in the stream gravels has been concen- 
trated from the bench gravels. The occurrence of gold has not been 
directly traced to a definite relation to any particular bed rock or to 
the quartz seams, which are rather common in the slates. Many of 
the dikes are more or less mineralized, and some of them are reported 
to carry values. Light-colored acidic dikes like those of the Forty- 
mile region, with associated quartz veins, were not observed in the 
Rampart region. The slates contain generally a large amount of 
carbonaceous matter, and anthracitic material is common in some of 
the small quartz seams. Pyrite is often found in both the slates and 
the quartz seams. On creeks where the conditions are apparently 
least complex the only rocks observed were carbonaceous slates and 
grits with quartz seams, which occasionally are a foot or more in 
thickness, and the monzonitic intrusives in the ridge about the head- 
waters. Many of the nuggets have a considerable quantity of quartz 
attached, and it seems probable that the gold has been derived from 
the small quartz seams. The only general fact which seems to empha- 
size itself is that the occurrence of gold in quantities of economic 
importance is limited to an area where deformation of the rocks has 
been intense and where there has been much igneous activity. 
