We had a long and hard day before us, but we did not know it when we set out from Tabuk at about seven in the morning. Gallman, Harris, and I kept together; our first business was to cross a vast, roughly circular plain fifteen miles in diameter, and densely overgrown with a rough, reedy grass two feet and more high. A foot-path ran across the plain, visible for only a very short distance ahead as long as one was in it, but imperceptible twenty yards to the right or left. To lose this path would have been a serious matter, as it would have been a heart-breaking thing to force one's way through the undisturbed grass. It would be hard to imagine anything else more wearisome than that fifteen-mile stretch. The sun was riding high in the heavens, "shining on both sides of the hill"; not a breath of wind was stirring nor was there, barring a rare bird or two, a sign of life save the thousands of flies which, as our ponies pushed aside the grass overhanging the path, rose in clouds only to settle on our faces, hands, necks, backs, everywhere. We began by brushing them off, but it was of no use, and so we rode with our faces turned to a dim haze of low mountains bounding the plain on the east, and themselves dominated by still another range, the Sierra Madre, so distant as to look like a bank of immovable blue cloud. For miles our plodding seemed to bring them no nearer. If we could only get out of that sea of olive-gray grass, on which the heavy, stifling air seemed to press, and reach those nearer mountains! Twice the path led us into sinks or depressions fully ninety or one hundred feet below the level of the plain; why these could not have been avoided when the path was first struck out is hard to imagine, unless it was to get to water. For one of these sinks boasted of a clear, bold stream with all of its course underground save the part in the depression. In both were full-grown trees and grateful shade. Had we not been pressed to get through, it would have been interesting to explore these huge sinks; but we passed on, the flies, which had abandoned us on our descent, rejoining us when we climbed out on the other side. In time we reached our mountains, arid, bare, eroded, wind-bitten, and made our way slowly and painfully up and through the pass, our trail hereabouts being nothing but a trench so deep and narrow that part of the way we could not keep our feet in the stirrups. As we neared the crest of the range the pass disappeared, and for the last half-mile or so we attacked the ridge directly. When we got to the top, we found a gallant breeze blowing, and, spreading out before us, the vast plains of the Cagayán Valley. Far over in the east, and apparently no nearer than ever, rose the blue, cloud-like mountains of the Sierra Madre, now showing like a wall, which indeed they are, and one which no man has so far succeeded in scaling. But not a sign of life, of man or beast, caught our eye.