In passing from the more fertile uplands to the lower plains, as they descended the streams, the timber on their banks became scarcer, and the groves more scattered. The rich buffalo or _grama_ grass was exchanged for a coarser species, on which the hard-worked animals soon grew poor and weak. The thickets of plum and cherry, of box-elder and quaking-ash, which had hitherto fringed the creeks, and where the deer and bear loved to resort--the former to browse on the leaves and tender shoots, the latter to devour the fruit--now entirely disappeared, and the only shrub seen was the eternal sage-bush, which flourishes everywhere in the western regions in uncongenial soils where other vegetation refuses to grow. The visible change in the scenery had also a sensible effect on the spirits of the mountaineers. They traveled on in silence through the deserted plains; the _hi-hi-hiiya_ of their Indian chants was no longer heard enlivening the line of march. More than once a Digger of the Piyutah tribe took himself and hair in safety from their path, and almost unnoticed; but as they advanced they became more cautious in their movements, and testified, by the vigilant watch they kept, that they anticipated hostile attacks even in these arid wastes. They had passed without molestation through the country infested by the bolder Indians. The mountain Yutas, not relishing the appearance of the hunters, had left them unmolested; but they were now entering a country inhabited by the most degraded and abject of the western tribes; who, nevertheless, ever suffering from the extremities of hunger, have their brutish wits sharpened by the necessity of procuring food, and rarely fail to levy a contribution of rations, of horse or mule flesh, on the passenger in their inhospitable country. The brutish cunning and animal instinct of these wretches is such, that, although arrant cowards, their attacks are more feared than those of bolder Indians. These people--called the Yamparicas or Root Diggers--are, nevertheless, the degenerate descendants of those tribes which once overran that portion of the continent of North America now comprehended within the boundaries of Mexico, and who have left such startling evidences in their track of a comparatively superior state of civilization. They now form an outcast tribe of the great nation of the Apache, which extends under various names from the Great Salt Lake along the table-lands on each side of the Sierra Madre to the Tropic of Cancer, where they merge into what are called the Mexican Indians. The whole of this nation is characterized by most abject cowardice; and they even refuse to meet the helpless Mexicans in open fight--unlike the Yuta or Comanche, who carry bold and open warfare into the territories of their civilized enemy, and never shrink from hand-to-hand encounter. The Apaches and the degenerate Diggers pursue a cowardly warfare, hiding in ambush, and shooting the