244 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. 
tity is rendered more or less uncertain. Each lens will be worked 
out in time and its place supplied by other lenses, and to what depth 
or distance the occurrences will go on it is quite impossible to state. 
The ore bodies may diminish, they may remain about the same, or 
they may increase. As judged by openings, tests by diamond drill, 
and surface outcrops, the deposit has a length of over a half mile, 
carrying bodies of ore throughout that distance. Large quantities of 
ore have been taken out, far greater quantities are now in sight, and 
there is every reason to expect a large output in the future. 
The minerals composing the ore and gangue were deposited at a 
time much later than the production of the inclosing rock. They are 
also younger than the period of deformation which produced the 
schistose arrangement in the granites. The minerals of the ore deposit 
are only slightly crushed or rearranged, although they arc the same 
varieties which, in adjacent formations, show the greatest metamor- 
phism. The ore deposit, therefore, was not due to original segrega- 
tion from the igneous granite, but is entirely of a secondary nature. 
It may have replaced a preexisting mass of rock by solution and sub- 
stitution of new minerals, or it may have been deposited from solu- 
tion in open spaces in the inclosing formation. This latter result is 
quite unlikely, on account of the great dimensions of the opening 
required by the size of the ore deposit. If the deposit represents a 
substitution of new minerals for old, the latter were either portions 
of the inclosing granite or a mass of a different original character. 
The shape of the ore deposits agrees with the general form taken by 
the smaller intrusive bodies in this region. The minerals composing 
the granite — quartz, mica, and feldspar — are among the least suscep- 
tible to chemical alterations. It is therefore probable that the rock 
replaced by the ore body had a less simple chemical composition. If 
the present minerals represent a recrystallization of those preexisting, 
the original rock might well have been a diabase similar to the Lin- 
ville metadiabase. This rock contains almost exactly the same min- 
erals as the ore deposit, but even the greater alteration through which 
it has passed has not produced anything in the nature of an ore. 
Accordingly, some additional or separate cause must be sought besides 
dynamic altera! ion. An agency fulfilling the conditions, and one thai 
is everywhere at work, is water charged with mineralizing agents. 
This dissolved and perhaps added to the rock minerals and redeposited 
them in favorable places, either in the old or in new chemical combi- 
nations. In this case the deposits have not the size or shape of veins, 
but are discontinuous and lenticular in shape, as above stated. They 
are plainly con trolled and directed by the schistosity of the granite in 
this and many other areas toward the west and southwest. 
There is no indication whether or not the channels through which 
the solution entered corresponded with the schistosity of the granite, 
although such correspondence is probable. In the red feldspathic 
