water courses or in such places as can be reached by turning running
water to them. Inasmuch as the water must flow from one to another,
there are practically no two sementeras on the same level which
are irrigated from the same water course. The result is that every
plat is upheld on its lower side, and usually on one or both ends,
by a terrace wall. Much of the mountain land is well supplied with
bowlders and there is an endless water-worn supply in the beds of
all streams. All terrace walls are built of these undressed stones
piled together without cement or earth. These walls are called
"fa-ning'." They are from 1 to 20 and 30 feet high and from a foot
to 18 inches wide at the top. The upper surface of the top layer of
stones is quite flat and becomes the path among the sementeras. The
toiler ascends and descends among the terraces on stone steps made
by single rocks projecting from the outside of the wall at regular
intervals and at an angle easy of ascent and descent (see Pl. LIII).

These stone walls are usually weeded perfectly clean at least once
each year, generally at the time the sementera is prepared for
transplanting. This work falls to the women, who commonly perform it
entirely nude. At times a scanty front-and-back apron of leaves is
worn tucked under the girdle.

In the Banawi district, south of the Bontoc area, there are terrace
walls certainly 75 feet in height, though many of these are not stoned,
since the earth is of such a nature that it does not readily crumble.

It is safe to say that nine-tenths of the available water supply of
the dry season in the Bontoc area is utilized for irrigation. In some
areas, as about Bontoc pueblo, there is practically not a gallon of
unused water where there is space for a sementera.