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.

A single area consisting of several thousand acres of mountain side is frequently devoted to sementeras, and I have yet to behold a more beautiful view of cultivated land than such an area of Igorot rice terraces.  Winding in and out, following every projection, dipping into every pocket of the mountain, the walls ramble along like running things alive.  Like giant stairways the terraces lead up and down the mountain side, and, whether the levels are empty, dirt-colored areas, fresh, green-carpeted stairs, or patches of ripening, yellow grain, the beholder is struck with the beauty of the artificial landscape and marvels at the industry of an otherwise savage people.

Irrigating

By irrigation is meant the purposeful distribution of water over soil by man by means of diverting streams or by the use of canals in the shape of ditches or troughs for conveying and directing part of a water supply, or by means of some other man-directed power to raise water to the required level.

The Igorot employ three methods of irrigation:  One, the simplest and most natural, is to build sementeras along a small stream which is turned into the upper sementera and passes from one to another, falling from terrace to terrace until all water is absorbed, evaporated, or all available or desired land is irrigated.  Usually such streams are diverted from their courses, and they are often carried long distances out of their natural way.  The second method is to divert a part of a river by means of a stone dam.  The third method is still more artificial than the preceding —­ the water is lifted by direct human power from below the sementera and poured to run over the surface.

The first method is the most common, since the mountains in Igorot land are full of small, usually perpetual, streams.  There are practically no streams within reach of suitable pueblo sites which are not exhausted by the Igorot agriculturist.  Everywhere small streams are carefully guarded and turned wherever there is a square yard of earth that may be made into a rice sementera.  Small streams in some cases have been wound for miles around the sides of a mountain, passing deep gullies and rivers in wooden troughs or tubes.