There are a number of formidable looking ranges of mountains upon all the maps, running across Arizona, north and south, which look to be barriers almost impassable without a great expenditure of time and money. Our road we found to be _through_, rather than _over_, these mountains; although they appeared formidable at a distance, yet, on approaching, they generally proved to be isolated buttes, with our road winding around them by easy grades through the valleys, or else passing over some low span or saddle, no way impeding staging. These passes in the mountains seemed to be formed by nature on purpose for a road. The speed our coaches are making through these mountain ranges is the best evidence of their easy and expeditious passage. By my journal of August 25, it will be noticed that the speed we made from Cook’s spring, through the Sierra Madre mountains to and beyond the Mimbres river, was 21 miles in five hours; through all the other mountain passes we made much the same rate of speed. Having formed my ideas of mountains and mountain roads from a pretty extensive experience among the Sierra Nevada of California, was very forcibly struck by the fact of not meeting a regular chain of mountains all the way from San Antonio until I reached the coast range of California, eighty miles from San Diego. I wish to call particular attention to the distinction between ranges of mountains like the Alleghanies and Sierra Nevada, and the system of isolated buttes scattered over portions of our line and around which we pass by valley roads well adapted to speed. The mountains south of the Gila, and its immediate neighborhood, do not interfere with our road; they come up close to the river in many places, but leave an ample passage way for our road around the bases. These mountains are mostly what the Mexicans term _Mesas_; high hills, flat on their tops. It appears as if the plain had formerly been level with the tops of the hills, some hundreds of feet higher than it is now. This same appearance of Mesas is found along the Pecos.