96 ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE. [bull.182. 
dependent upon kind of country rock or direction of Assuring. Finally, 
emphasis should again be laid upon the fact that there is much over- 
lapping and intermingling of types, and that ores of many kinds may 
occur in any given limited district. Free-gold ores, in particular, may 
be expected to occur in any part of the quadrangle. 
DISTRIBUTION OF THE ORES WITHIN THE LODES. 
Lodes are seldom equally well mineralized in all portions. Those 
parts of a lode or vein which are sufficiently large and rich to be 
profitably worked are commonly known as pay shoots or ore shoots, 
sometimes spelled ore chutes. The first term is regarded as prefer- 
able, inasmuch as it expresses concisely the thing meant, and can not 
be confounded with the ore chutes or mill holes of timber through 
which ore is drawn from the stopes into the mine levels. A pay shoot 
is obviously not a thing capable of exact delimitation. Its size and 
shape depend to some extent on fluctuations in the metal market 
(unless purely a gold ore) and on variations in the operating expenses 
of the mine. But the concentration of ore in certain portions of a 
lode separated by unprofitable lode matter is a very important phe- 
nomenon, and one that can, as a rule, be studied and discussed only 
as it is revealed in the exploitation of pay shoots by actual stoping. 
A complete study of pay shoots requires good stope maps, carefully 
revised to date, and an advanced stage in the development of the 
lodes. Except for a few localities, these favorable conditions are not 
found in the Silverton quadrangle. The advantage in all future 
development of having a record of past work is not always fully 
realized, and the miner is too often content simply to follow his ore 
where he finds it, adapting his work merely to the needs of to-day. 
In simple lodes with continuous pay shoots this rough-and-ready 
mining may succeed well enough. But in complex lodes, or in groups 
of lodes, such as those of the Silver Lake mine, systematic mapping 
and the adaptation of the development to future probabilities may 
mean success where the more ordinary method would result in failure. 
On account of the general absence of accurate stope maps and the 
small depth of most of the mines operating in the quadrangle the 
following observations on the pay shoots are fragmentary and often 
unsatisfactory. 
In most of the workable veins and simple lodes, such as those of 
Sultan Mountain and Silver Lake Basin, pay ore is usually, although 
not invariably, found wherever the fissure is wide enough to hold an 
ore body. This appears to be particularly true of the New York City, 
Stelzner, Royal, and Iowa veins. Thus, in these veins, distinct pay 
shoots, separated by stretches of barren lode, do not properly occur, 
or have not been demonstrated by mining operations. The pay shoots 
take their shape, as a whole, from the form, of the fissure. A partial 
exception to this is found, however, in the impoverishment of the 
