10 at the bottom, and is about 300 feet long. It is built each year
during November and December, and requires the labor of fifteen
or twenty men for about six weeks. It is constructed of river-worn
bowlders piled together without adhesive. The top stones are flat on
the upper surface, and the dam is a pathway across the river for the
people from the time of its completion until its destruction by the
freshets of June or July.

The upper dam is a new piece of primitive engineering. It, with its
canal, has been in mind for at least two years; but it was completed
only in 1903. The dam is small, extending only half way across the
river, and beginning on an island. This dam turns water into a canal
averaging 3 feet wide and carrying about 5 inches of water. The
canal, called "a'-lak," is about 3,000 feet long from the dam at A
in Pl. LVII to the place of discharge into the level area at B. For
about 530 feet of this distance it was impossible for the primitive
engineer to construct a canal in the earth, as the solid rock of
the mountain dips vertically into the river. About fifty sections
of large pine trees were brought and hollowed into troughs, called
"ta-la'-kan," which have been secured above the water by means of
buttresses, by wooden scaffolding, called "to-kod'," and by attachment
to the overhanging rocks, until there is now a continuous artificial
waterway from the dam to the tract of irrigated land.

Considerable engineering sense has been shown and no small amount of
labor expended in the construction of this last irrigating scheme. The
pine logs are a foot or more in diameter, and have a waterway dug
in them about 10 or 12 inches deep and wide. These trees were felled
and the troughs dug with the wasay, a short-handled tool with an iron
blade only an inch or an inch and a half wide, and convertible alike