National Geographic : 1896 Apr
SERILAND feet, and fully 5 out of the 71 miles of the low cliff reveal the sub stratum of planed granite beneath a torrential veneer, while there is more of alluvium-free granite than of graniteless alluvium. The sharp contrast between mountain and plain is doubtless due to the character of the scant rainfall; but the relation need not be further pursued at present. Hardly less striking than this general topographic relation are the strong local features of the topography. Tiburon island is but 30 miles long and less than 20 wide, yet it contains several ranges, the dominant one (Sierra Kunkaak) of Alpine ruggedness throughout most of its 4,000 feet of altitude. Sierra Seri is an imposing assemblage of peaks, aretes, precipices, and profound gorges, cutting the azure at fully 5,000 feet, though the width of the range from strait to desert is but 10 miles. Even more impressive than the mountains, to the explorer on the ground, is Desierto Encinas-the broad waste of playas and sand dunes lying over against the Papago of old, the law-bound Sonora of today. Toward its broad basin-shape ex panse storm freshets flow apparently from all directions, yet it is never filled and rarely wetted, and the scant water sometimes rising to the surface on its steeper western slope is saline; it is partly barred from the gulf and lined in its lower levels by a sheet of sediment charged with recent marine shells, which show that at no remote day it was an arm of the sea. Of interest, too, is the gale-swept strait El Infiernillo, for the foot-slopes on island and mainland are just such as sweep down and merge between the parallel ranges of the interior, and extend nearly or quite to the coastline where they are cut by wave-carved cliffs or pass into current-built sand-spits, making it manifest that the strait was originally a subaerial valley like those of the interior and only recently occupied and slightly modified by the sea. Isla Tassne, too, is a noteworthy feature; though but a fraction of a mile in any dimension and for the most part a wave-built bench, its nucleus is a 500-foot spire of rock, the half-submerged crest of a twinned peak on which myriads of water fowl nest. The topographic detail of Seriland is that of water-carving or water building, yet the aridity is such that the work must proceed at infinitesimal rate. The dearth of water is a burning ques tion to the explorer, a vital element in prospective conquest of Seriland for the behoof of civilized man. In all the half dozen valleys, the hundred barrancas, and the thousand storm-cut gorges, there are probably less than a dozen nominally perma nent, and but two or three actually permanent, sources of fresh water in the territory.