more resembles igneous rocks than limestone. Having arrived at the foot of the sand hills, we commenced travelling very slow. There was nothing around us but the deepest and purest sand, and the animals could only get along in the slowest walk, and by resting at short intervals. At last my animals were exhausted; they would move no more, and we had not yet reached half of our way. In this dilemma I put my own riding horse to the wagon. Mr. Jacquez lent me some additional mules, and forward we moved again. In the meanwhile dark night had come on, illuminated only by lightning, that showed us for awhile the most appalling night-scene–our wagons moving along as slow and solemn as a funeral procession; ghastly riders on horseback, wrapped in blankets or cloaks; some tired travellers stretched out on the sand, others walking ahead, and tracing the road with the fire of their cigarritos; and the deepest silence interrupted only by the yelling exclamations of the drivers, and the rolling of distant thunder. The scene was impressive enough to be remembered by me; but I made a vow the same night, that whenever I should undertake this trip again, I would rather go three days around, than travel once more over the sand hills with a wagon. About midnight, at last we reached the southern end of the sand hills, and encamped without water.
August 17–On better road, we travelled this morning about 12 miles, and halted at a pool of rain water. The soil becomes now firmer, contains more clay than sand, and makes as good a wagon road from here to Chihuahua as if it were macadamized. The plain through which we travel is east and west, lined by mountains, and is 15 to 20 miles wide. The mountains are timbered with a few scanty cedars, and some pine trees; the geological formation is granitic and porphyritic. The grass becomes every day better, and looks as fresh as in spring. The so-called gramma grass, which grows here very fine, is especially liked by our animals. A small caterpillar covered it in great numbers. On the mezquite shrubs, too, some insects become very common, a great many spectra especially, and a large centipede of flattened form and dark brown color.
In the afternoon we travelled 15 miles more and camped again in the prairie, with plenty of rain-water. About five miles before we went to camp, I made an excursion to a cave to the left of our road. The cave was in a small isolated mountain, composed of amygdaloidal basalt and porphyritic rocks. It was towards sunset when I approached it, and the mountain, with the grotto, looked quite mysterious. Two ravens, sitting before it on high palmillas, seemed to guard the entrance, and an owl flew screaming over my head as soon as I dared to enter it. Inside I found a small lake of pure fresh water, with sediments of limestone, but it was already too dark for further examination.
August 18.–Made in the morning 15 miles, and camped again in the prairie, on a water pool. In the forenoon we passed Ojo Lucero (Venus spring,) and Laguna de Patos, (lake of geese.) The first is a fine spring, only a hundred yards to the left of our road. The water comes out of a small, sandy basin in the prairie, but with considerable force; it is clear and soft of tastel the temperature of the spring was 77.5° Fah., while the atmosphere in the shade was 81° Fah. A little creek, formed by it, crossed the road, and spread to the right of it into a small lake. Some miles ahead, to the left of our road, but more distant from it, a larger lake is seen in the plain, the Laguna de Patos; it is the outlet of the Rio Carmen. Between the Ojo Lucero and lake Patos, but to the right of our road, rises
