National Geographic : 1898 Aug
PAPA G UERIA This characteristic waterflow has reacted on the topography during the eons of geologic history, and has developed a config uration no less distinctive than the drainage systems. To the traveler by rail along the northern border of Papagueria the region seems one of remarkably rugose and irregular mountain ranges, buttes, picachos, and precipice-walled mesas; for the jagged mountains are always in sight and the clear air brings them close to the eye. At first the traveler in the saddle sees the region in similar light, the exceeding ruggedness of the mountains giving them undue prominence; but after spending days in traversing the intermontane plains and hours in cross ing or circumscribing ranges and mesas for a month or two he learns to see the land-forms in true proportion, and finds that only a fifth or a tenth of the surface is mountain and four-fifths or nine-tenths plain or valley so smooth as easily to be traversed by pack-animals, and for the most part by wheels. So rugged are the mountains and so smooth the plains that the region has been likened by a careful observer to a series of great ranges buried to their ears in alluvial deposits; yet more thoughtful study shows that half the area of the plains is smoothly planed rock similar to that of the mountains, the planing being the work of the sheetfloods into which the freshet waters gather. In gen eral, the plains incline toward the great trough half filled with the waters of the Californian gulf; and, on crossing the north westerly-southeasterly trending ranges toward the gulf, each in termontane plain is found to lie lower than the last, down to the tide-swept shore. This inclination is a part of that southwest ward tilting which accompanied the uplifting of the great plateau region and the birth of the Colorado canyon. In arid Papa gueria, where the work of the feeble streams is long drawn out, it has resulted in a regressive erosion, whereby the streams flow ing southward and westward have cut far into and often through the ranges in which the waters gather, pushing the divides into the plains beyond. The habitability of Papagueria is largely due to this fact, for it is only in the narrow gorges cut into and through the ranges by regressive stream-work that the scant ground-water approaches the surface in springs or seepage from the sand-washes.* The Papago Indians, primitive and present holders of this dis trict, are preeminently children of the desert. So strongly ad *The topography and its development in this interesting region are set forth in greater fullness in "Sheetflood Erosion" (Bull. Geol. Soc. Am., vol. 8, 1897, pp. 87-112).