This is at the top of the barranca.
Then imagine a valley a mile or two in width, with sides almost perpendicular and capped with basaltic pillars, and at the bottom a strip of land where the vegetation is of the deepest green of the tropics, with a river winding along among palm-trees and bananas.

This great barranca is between two and three thousand feet deep, and the view is wonderful.

We went down a considerable way by a zig-zag road, my companion collecting armfuls of plants by the way, but unfortunately losing his thermometer, which could not be found, though a long hunt for it produced a great many more plants, and so the trouble was not wasted.

The prickly pear was covered with ripe purple fruit a little way down, and we refreshed ourselves with them, I managing--in my clumsiness--to get into my fingers two or three of the little sheaves of needles which are planted on the outside of the fruit, and thus providing myself with occupation for leisure moments for three or four days after in taking them out.
Many species of cactus, and the nopal, or prickly pear, especially, are full of watery sap, which trickles out in a stream when they are pierced.

In these thirsty regions, when springs and brooks are dry, the cattle bite them to get at the moisture, regardless of the thorns.