160 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. 
The copper deposits. — Considered in the most general waj 7 , the 
deposits of copper in the region fall into two classes. The first class 
includes all where the mineral is chalcopyrite or copper- bearing pyrite 
unaccompanied by oxides, carbonates of copper, or rich sulphides, 
except very superficially where the former minerals have been oxi- 
dized by surface weathering. Deposits of this sort, which occur 
invariably inclosed in undecomposed or "live" rock, are regarded as 
original ores. Their distribution is almost universal, and they are 
found in all sorts of rocks, frequently without any recognizable vein 
material, but sometimes accompanying masses of quartz with a small 
amount of feldspar, calcite, or siderite (carbonate of iron). In those 
cases where little vein matter is present the ore occurs, as a rule, in 
pockets or lenticular masses following the schistose or platy structure 
of the country rock, and more or less mixed with the inclosing mate- 
rial. No instances were observed where bodies of this character gave 
promise of sufficient size or permanence to warrant the expectation 
that they will lead to important masses of ore. 
As an exception to deposits of the above type where there is no 
well-defined lead traceable for any considerable distance upon the 
surface, there are others, still without associated quartz, occurring in 
strong leads traceable for long distances upon the surface. A typical 
example of this variety of deposit is the Verde or Ilinton property. 
The Verde lead is a zone along which intense metamorphism has taken 
place, involving hornblende-schists, a band of limestone, and some 
thin strata of quartzite. The lead seems to follow the limestone, 
which in turn appears to lie parallel to the general schistosity of the 
region. There is every reason to anticipate that metamorphic zones 
of this kind will persist in depth, though the extent to which copper 
has been deposited in them must be proved by exploration. 
In a third type of original ores the copper pj'rites occur in a 
matrix of quartz accompanied by calcite and siderite or by feld 
spar. The sulphide here occurs in bunches throughout the mass of 
the gangue, and the value of such veins is dependent upon their per- 
sistence. Some veins of this nature are lenticular bodies lying with 
their longest surface dimensions parallel with the platy structure of 
the inclosing rock. Certain of such masses of quartz reach a width 
of 50 feet or more, showing in outcrop a length of from twice to sev- 
eral times this figure, but these seldom show any considerable amount 
of copper, though they are reported to cany a small amount of gold. J 
They can hardly prove to be permanent in depth. In other cases the!; 
quartz occurs in a disconnected series of thinner lenses, extending 
along the same general trend in the schistose rocks. Sometimes these 
interrupted veins carry chalcopyrite in promising amounts. Their 
probable downward extent and regularity may be closely ascertained' 
by a study of their persistence along their strike. If they are irregu 
lar and interrupted upon the surface, they are likely to be discon 
