When two veins cross each other, one may be
auriferous on one side of the intersection and not on the other; but in
this case the other vein will be auriferous on both sides. It is as
though they were streams, one rich, the other barren, and that after
meeting, the wealth of the one was divided between them. It is a
general rule that metalliferous veins running parallel with the strata
of the bed-rock or country are not extensive. In fact they are rather
deposits than veins, and though often extremely rich are soon
exhausted, while the lodes which run across the stratification, run far
and deep, and have a regular and straight course and dip. Lodes lying
between two different kinds of rock, are usually richer than those
which have the same kind of rock on both sides. Thus it is said that
the richest veins of auriferous quartz in California, have been
discovered at the intersection of trap and serpentine, and the richest
places in veins are where they cross from one kind of bed-rock into
another. The richest part of a lode of auriferous quartz is almost
invariably on the lower side of the vein, near the foot-wall. All these
are facts to be remembered by the prospector as a guide, and an
assistance to him in his search for a rich gold-bearing vein. If the
lode is covered with earthy matter, he may sometimes trace its course
by the difference in the color of the dirt and stones over it from that
elsewhere. When the prospector finds dirt and stones on a vein,
evidently disintegrated portions of it, he should wash some of the dirt
in a pan, and if he finds no gold, there is a strong presumption that
the vein is barren.

_Prospecting Quartz Rock._--After finding a gold-bearing vein, the
question arises whether it will pay. Great sums are lost in gold-mining
countries by injudicious investments in mills and machinery to work the
auriferous rock, and persons going into the business should be
particularly careful not to commit this great error. The business of
quartz mining has great profits, but also great pecuniary dangers
connected with it. It is rarely that all the rock of a vein will pay
for working. In some lodes, the vein-stone will average one hundred
dollars to the ton, for all the stone found in a certain part of the
lode, but beyond that the rock may be poor or worthless. Picked
specimens may be worth several thousand dollars to the ton, but perhaps
not more than a ton of such specimens has been obtained in the best