Juan Pablo García (thumb print) José Louis Valle (thumb print) James Brown (thumb print) San Juan Shurtewa (thumb print) Thomas Lucio (thumb print) Henry C. Routzin Governor (thumb print) John C. García Interpreter James H. Miller Frank Ortiz Chapter X ORIGINS AND MIGRATIONS The aboriginal migrations of man in the Southwest may be roughly likened to the spread of vegetation or to the stocking of regions by animals from a center of distribution. Two great movements can be detached, one setting from the Rio Grande toward the west and south, and the other from the Gila toward the north and east. An objective region for both was the valley of the Little Colorado which offered an attractive home for all the tribes.—FEWKES. From primeval times there were in the Southwest four geographic regions to which the aborigines naturally gravitated, because of their favorable river systems. These were the basins of the Rio Grande, the San Juan, the Little Colorado, and the Gila. “Here the ancient ruins are most numerous, and life seems to have been more active and intense than elsewhere.”[107] The ancient pueblo region extends from Great Salt Lake southward into Mexico, and from the Grand Canyon eastward to the Pecos River. This region comprises 150,000 square miles. In certain portions of it ruins are to be found by the thousands. Usually they are clustered together in villages, but there are, besides, scattered ruins that probably indicate outlying settlements on the farm lands of the community. Prehistoric migrations were due to various causes. Preëminent among them was the search for water, that primal necessity of existence. The need of salt for men and animals was another factor in the choice of settlement of aborigines as well as of the later frontiersmen.[108] New Mexico, Arizona, and the Great Basin are peculiarly rich in saline deposits, which no doubt had their part in attracting population.[109] Salt might also be a cause of emigration. Fewkes shows that land long irrigated may become so saline as to be useless for agriculture, and he says, “This cause was perhaps more effectual than human enemies or increased aridity in breaking up the prehistoric culture.”[110] The hostility of neighbor clans or neighbor tribes often drove tribes to positions that could be more easily defended.