weed.] CONTINUANCE OF VEINS IN DEPTH. 15 
by planes dipping 61° E. and crossing the vein at 90°. The out- 
crop of the vein is traceable westward up the slopes by its rusty quartz, 
and a nearly continuous ledge can be followed. This outcrop has been 
opened at intervals of a few yards by trenches, which expose the vein 
and show it to have a thickness of from 2 to 6 feet, with about half 
this thickness of ore. No samples were, however, taken, and it is uncer- 
tain whether the altered granite does not contain a percentage of tin 
oxide. The most westerly working that could be surely identified as 
being upon the north vein is a pit 6 feet deep, which shows a 6-foot 
vein in which the quartz is bluish in color and the tin ore is associated 
with much pyrite. This point is about 600 or more feet west of the 
first shaft. West of this point the ledge can not be traced across the 
slopes, but an opening north a hundred feet higher and a few hundred 
feet farther west shows a good vein, carrying much pyrite, but devoid 
of any recognizable tin ore. 
The middle vein is developed by a shaft 50 feet deep, which shows a 
vein having a central leader of quartz 2 feet wide at the top and taper- 
ing to 1 foot 4 inches wide at the bottom of the shaft. The dip, as 
shown by the walls of the shaft, is 70° N. The central quartz mass is 
spotted with cassiterite, and the altered granite on either side contains 
recognizable grains of tin oxide. 
The south vein lies 500 to 600 feet south of the middle vein. This 
vein is much narrower than the veins on the north, having an average 
I width of about 1 foot. The strike, as shown near the shaft, is N. 50° 
1 W. and the dip 50° N. The vein walls are sometimes defined by a clay 
I selvage one-sixteenth inch wide, but more often show a gradual fading 
off into the granite. 
CONTINUANCE OF VEINS IN DEPTH. 
It will be noticed from what has been said that the veins are all well 
defined at the surface and carry good values in tin ore, but that the 
ore apparently dies out in depth. Further development is needed to 
establish the existence of the ore at a greater depth than 50 feet, but 
it is believed that the veins have been thrown by local slips or faults 
and will be found by crosscutting from the bottom of the present 
workings. The character of the fissures and the nature of the ore 
both indicate that the veins are the result of deep-seated agencies, and 
are not merely segregations due to descending surface waters. For 
this reason it is believed that further exploration will develop well- 
defined tin veins. The absence of topaz in the deposit is noteworthy, 
for this mineral is commonly associated with cassiterite veins the world 
over. In other respects the deposits closely resemble the tin veins of 
Europe, and are clearly due to metasomatic processes. The evidence 
of a pneumatolitic origin is, however, not conclusive. 
O 
