As stated in a previous chapter, all of the Indian tribes occupying the region in the vicinity of the Yosemite Valley were more or less affiliated by blood and intermarriage and resembled each other in their customs, characteristics and religious beliefs. What is said, therefore, on these subjects in the following pages, will be understood to apply generally to all of the tribes which have been mentioned as inhabiting this region, although, of course, minor differences did exist, principally due to environment. As in the case of all primitive peoples, their mode of life, food supply, etc., were largely determined by natural conditions, and the tribes living in the warm foot-hills differed somewhat in these respects from those dwelling higher in the mountains. DIVISION OF TERRITORY. In their original tribal settlements, at the time the first pioneer whites came among them, the Indians had well defined or understood boundary lines, between the territories claimed by each tribe for their exclusive use in hunting game and gathering means of support; and any trespassing on the domain of others was likely to cause trouble. This arrangement, however, did not apply to the higher ranges of the Sierras, which were considered common hunting ground. COMMERCE AMONG THE TRIBES. As there was a difference in the natural products and resources of different sections of the country, there was a system of reciprocal trade in the exchange of the different desirable commodities. Sometimes commerce between tribes extended for a long distance, as, for instance, the Indians on the western side of the Sierra Nevada Mountains were entirely dependent upon the Pai-utes _(Pye-yutes')_ on the eastern side for the obsidian, a kind of volcanic glass, from which they made the points for their most deadly arrows, used in hunting large game or when in mortal combat with their enemies. They were also dependent upon the Pai-utes for their supply of salt for domestic use, which came in solid blocks as quarried from salt mines, said to be two days' travel on foot from Mono Lake. From the Indians at or near the Catholic Missions to the South, on the Pacific Coast, they got their hunting knives of iron or steel, and sea shells of various kinds, for personal or dress ornaments, and also to be used as money. From the same source they obtained beads of various forms, sizes and colors, cheap jewelry and other fancy articles, a few blankets, and pieces of red bunting, strips of which the chiefs and head men wore around their heads as badges, indicating their official positions. COMMUNICATION.