TOPOGRAPHY. The extension northwestward of the Mexican Cordilleras, which rises beyond the Colorado River in the Sierra Nevada, divides Arizona diagonally into two regions—a south western part of low elevation, and a northeastern part consisting of an elevated plateau. The whole Territory, however, is mountainous in the limn of short, isolated ranges having a general north west-southeast trend, which are abrupt, sterile, and gashed by deep canons and dry water-courses. In the south these mountains rarely reach 3000 feet in height, but in the central line of eleva tions they are more continuous and lofty, many summits approaching 10,000 feet (Thomas Peak, 11,496; Ord Peak, 10,266; Bill Williams Moun tain, 9264; Mount Logan, 7700; Mount Tipton, 736 I; Mount Dellenbaug,h, 6756, etc.). The Highest mountains in the Territory are in the isolated San Francisco Range, in the northern central part. the apex of which reaches 12,794 feet. From those central elevations the Territory slopes rapidly away nearly to sea level in Gila Valley. The northeastern half of the Terri tory consists of a broken, eafion-cnt, lull-studded, arid table-land, the average altitude of which is over 5000 feet above the sea, with many large areas from 6500 to 8000 feet. The few, and often intermittent rivers, which drain this arid region, serving more as the conduits of sudden rainstorms than as living water - courses, run in narrow cations. in some cases a mile or more deep. The
Ilio Colorado (sec ('OLORADO RIVER) traverses the northwest corner of the Territory in such gorge, and then. turning to the south, be comes the western boundary of Arizona to near its mouth. Its tew tributaries, of which the Lit tle Colorado in the north alone is important, reach the river through similar ealions. The whole scenery of this no•thWestern part of the Territory is that of a rough, rocky, dry region, interrupted by steep-sided gorges and scarp fronted mesas and barren inountains, more or less covered with bunch-grass and scattered, stunted trees. The southern part of the Terri tory is, on the whole, even more desert-like in appearance, and all the- water-courses (most of which are dry except for a short time after rains) lead downward to the Gila. a broad, shallow river flowing into the Colorado near its mouth. The mountains here are mainly of volcanic origin. The only other rivers in Arizona worth mention ing are the Rio Santa Maria and Saildy, which unite in the central western region to form Bill Williams Fork, which enters the Rio Colorado near latitude 34° N., and the Virgin, in the ex treme northwest corner of the Territory.