The walls are not vertical, but incline somewhat toward the slope on which they are erected.

The terrace thus formed is often filled with soil to the height of the wall-top for a space of from fifteen to twenty feet.

Earth taken from them does not show any colours.

Some of these trincheras measure thirty feet in length by four feet in height, while the smallest ones I saw were only five feet long and three feet high.

Naturally enough, the largest ones are in the lower part of the gullies; then, some twenty-five feet back and above, others almost as large may be found.