e water arrives upon it, and disputes
may arise between the shareholders of the canal and the mining company,
ending frequently in the one devouring the other, unless the two interests
be quickly amalgamated.

The starting point should be the lowest level, or "bed rock," on the white
cement in the ancient channel, which is probably the original silt
collected in it, and is harder than the conglomerate above it, which is
more easily removed. The courses of these beds can be easily traced by
landmarks and undulations, and occasional exposures of the bed rock at low
levels; also trial shafts are sunk in various places in search of it, to a
depth of 100 feet, passing through blue gravel. The grades of these beds
are not steep, being from 10 to 40 feet per mile as of an ordinary river,
and the calculated thickness of the alluvial conglomerate is about 600
feet in many places across the ridge between the South and Middle Yuba
River across the Columbia.

The power of the water for the operation is dependent on a given volume
deposited in a reservoir, and at sufficient elevation above the points of
discharge, as on this depends effectivity to tear down the gravel. It is
delivered to the miner by huge pipes made of wrought iron, and laid down
to follow the curvatures of the surface of the ground; and the pipe I now
treat of, belonging to the Excelsior Water Company, has a diameter of 40
inches on a length of 6,000 feet, and 20 inches on the rest of its length
of 8,000 feet, being 9,000 feet in all; and this large pipe forms an
inverted siphon across a valley, following on the gravel, to the top of
the hill into the reservoir.

These pipes offer advantages over wooden aqueducts for spanning chasms,
and also to avoid coursing the sides of valleys; being also cheaper to
construct in general, and less liable to accidents from fire and storms,
and have the convenience for conveying the water from point to point, as
the work of excavation advances, necessitating the removal of portions of
the aqueduct forward. The watershed, or reservoir, of the Excelsior
Company embraces the valley of the South Yuba and its affluents, and the
entire cost of its eight amalgamated canals was 750,000 dollars.

The rainfall during three years in the mountains averaged 49 inches
annually, while the medium in the same period did not exceed 20 inches in
the plains beneath. The height of the reservoir above the tailing, or Yuba
River, is 393 feet: and the