The next day we reached the Rio Grande del Norte. This we found frozen over, and we camped on the river bottom, which is thickly timbered with cottonwood and willow. Here my feet and those of several others were frozen--the result in part of wearing boots, for which I quickly substituted moccasins, with blanket wrappers, which are much warmer than socks, and which, with leggings of the same material, afford the best protection for the lower extremities against severe cold.
Continuing up the river two or three days, we again entered the mountains, which soon assumed a very rugged character. Nature, in the ascent towards the Sierra Madre, presents herself with all her features prominent and strongly marked, her figures bold and colossal. Our progress became slow and laborious. Our track lay through deep mountain gorges, amid towering precipices and beetling crags, and along steep declivities where at any other season it would have been next to impossible to travel, but where now the deep snow afforded a secure foothold. In making the ascent of some of these precipitous mountain sides, now and then a mule would lose its footing and go tumbling and rolling many feet down. My saddle mule took one of these tumbles. Losing her foothold, she got her rope hitched upon a large log which lay loosely balanced on the rocks, and, knocking me down and jerking the log clear over my head, they went tumbling down together. But fortunately no one was hurt. A great obstacle to our progress were the rapid, rough-bottomed, but boggy streams which we had frequently to encounter in the deep and narrow ravines, where the mules would get balked, half a dozen at a time, with their packs on. Then we had to wade in up to our middle among the floating ice in the freezing water to help them out.
The farther we went the more obstacles we had to encounter; difficulties beset us so thickly on every hand as we advanced that they threatened to thwart our expedition. The snow became deeper daily, and to advance was but adding dangers to difficulties. About one-third of the men were already more or less frost-bitten; every night some of the mules would freeze to death, and every day as many more would give out from exhaustion and be left on the trail.... Finally, on the 17th of December, after frequent ineffectual attempts, we found that we could force our way no farther. By our utmost endeavors with mauls and spades we could make but half a mile or a mile per day. The cold became more severe, and storms constant, so that nothing was visible at times through the thick driving snow. For days in succession we would labor to beat a trail a few hundred yards in length, but the next day the storm would leave no trace of the previous day's work. We were on the St. John Mountain, a section of the Sierra Madre and the main range of the Rocky Mountains proper. At an elevation of 11,000 feet the cold was so intense and the atmosphere so rare that respiration became difficult; the least exertion became laborious and fatiguing, and would sometimes cause the blood to start from lips and nose. The mercury in the thermometer stood 20° below zero, and the snow was here from four to thirty feet deep. When we built our camp-fires deep pits were formed by the melting of the snow, completely concealing the different messes from each other. Down in these holes we slept, spreading our blankets upon the snow, every morning crawling out from under a deep covering of snow which had fallen upon us during the night. The strong pine smoke,--for here there was no timber but pine,--together with the reflection from the snow, so affected our sight that at times we could scarcely see. The snow drifted over us continually, driven about by the violence of the chill blasts which swept over the mountains.