As winter was approaching and the days were now becoming considerably shorter, it was incumbent upon me to hasten my departure from Omaha, if I would reach my destination as contemplated at the outset. Having learned from frontiersmen that Eastern horses are not available in the Alkali Region of the Plains, I placed my faithful _Paul_ in a boarding stable in Omaha, purchased a mustang of a Pawnee Indian and forthwith continued my journey westward. Webster defines a _mustang_ as the "Wild Horse of the Prairie." My experience with him has taught me that he is sufficiently docile under the restraint of a tight rein; will travel a longer distance over a rough road in a given time than the average horse, and scarcely ever shows fatigue even if the road is all up-hill. Of course, some of them are vicious, and will make things uncomfortable for the rider; but in this particular some civilized horses are not unlike them. I found the Mexican saddle more convenient than the "McClellan" which I had hitherto used, and thought much easier for the animal. [Illustration: NORTH PLATTE, NEBRASKA.] My mustang proved tractable and made excellent time; and having obtained in Omaha all the information within my reach concerning the remaining half of my journey, I determined to use all despatch and avoid as far as I could the cold weather of the Rockies and Sierras. I may here state that in consequence of the long rides I was now compelled to make, with very few stoppages except at night, the original plan of the journey was somewhat changed, and my journal necessarily fell into disuse; my chief object being to get over the mountains as quickly as possible. I was, therefore, unable during the remainder of my ride to refer so much to daily incidents, but confined myself to jotting down in a general way whatever I thought might prove of interest to the reader. Over the Great Plains that lie between the Missouri and the Rockies my nerve was thoroughly tested, and not less so the mettle of my mustang which carried me a distance of five hundred and twenty-two miles in six days. Halts at this time were few and far between, except for necessary food and sleep. The weather had become very cold since leaving Omaha, and the ascent had been gradual but continuous.