CHAPTER III.

PHYSICAL AND GEOLOGICAL FEATURES.

THE TOPOGRAPHY OF ARIZONA. PROFESSORS BLAKE AND PUMPELLY. MOUNTAIN RANGES. THE LAVA FIELD. CONES AND PEAKS. THE GRAND PLATEAU. ITS GEOLOGY. DR. NEWBERRY'S WORD PAINTING. THE CAÑON SYSTEM OF THE COLORADO. MAJOR POWELL, THE EXPLORER. VIVID DESCRIPTION. NAVIGATION. THE GILA, COLORADO-CHIQUITO, ETC. A TOPOGRAPHICAL BOND OF UNITY.

Arizona, physically considered, consists of a series of wide plateaux, generally having a mean elevation of from but 60 to 100 feet on the south-west, up to 6,000 and 7,000 feet above sea-level in the north. These plateaux are crossed by mountain ranges, while magnificent peaks diversify the prospect. They are riven in all directions by great cañons, vast gorges, deep channels, cut by the streams and rivers which, since the mysterious Archæan ages, have been forcing their way through this huge mass of mountain formation. Nowhere else can the operations of world-making be observed with more distinct and positive clearness than in the geology and physical character of the larger portion of this Territory. Professor J. D. Whitney thus sums up, and inadequately, too, the general aspect of the region:*

"From Mexico, the system of the Cordilleras enters our Territory still widening and gaining in perplexity. Just above the southern border of Arizona, along the parallel of 33 deg., occurs the greatest depression of the Cordilleras existing north of southern Mexico; here the continent may be traversed without rising to an elevation of over 4,000 feet. The country along this line is a table-land, with many short and broken ranges of no great altitude built upon it, but deeply excavated by numerous cañons, * of which that of the Colorado River may be taken as a type. On this plateau, in latitude 35 deg., there is a transverse east and west line of volcanoes, similar to that which traverses Mexico; these grand volcanic cones, of which the

*

*Physical Aspects of the United States. Statistical Atlas, 1874.

PLAINS OF THE SOUTHWEST-LAVA.

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San Francisco Mountain is the loftiest and best known, rise to nearly double the altitude of the plateau on which they are built up." * "Lava plains of great length and breadth are found along the Gila River."

*

Profesor Pumpelly describes the south-west portion of Arizona from the Sonora line to the Gila River, in the following terms: "Broad, gravelly plains, bearing only cacti, with here and there the leafless palo-verde tree and the never-failing greasewood bush. In the distance, on either side, arise high granite mountains, to which the eye turns in vain for relief; they are barren and dazzling masses of rock. On these vast deserts the sluggish rattlesnake meets the traveller at every turn; the most powerful inhabitant, his sway is undisputed by the scorpions and lizards, on whom he feeds. The routes over these wastes are marked by countless skeletons of cattle, horses and sheep, and the traveler passes thousands of the carcases of these animals wholly preserved in the intensely dry air. Many of them dead, perhaps for years, have been placed upright on their feet by previous travelers. These mummies, they seemed sentinels guarding the valley of death."*

* *

Over the center of the arid plains thus described, there stretches, from north to south, a mass of lava about one mile wide, and extending southward as far as the eye can reach. On this lava wall stand two parallel rows of extinct volcanic cones 100 to 300 feet high, with craters. "In crossing this remarkable remnant of recent volcanic action," writes Professor Pumpelly, one could look down the long and perfect vista of regular cones till they faded away in the perspective and behind the curvature of the earth."

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Prior to the Wheeler expedition of 1873 it was not known that within the borders of Arizona and New Mexico there lies one of the great lava tracts of the world, a continuous area of volcanic products, second in magnitude in our country only to the great north-western lava field, and fifteen times as large as the classical district of extinct volcanoes in Central France. The geologists who have accompanied the various public and private railroad surveys have passed, on the thirty-second parallel, to the south of it, or on the route of the thirty-fifth parallel have missed the main body and touched only its extended arms. Messrs. Marcou and Newberry, who saw Mount Taylor and Mount San Francisco, two hundred and thirty-five miles apart, had no means of knowing that by a detour to the south

*Across America and Asia.

they could pass from one to the other almost without walking on other rock than lava, and yet such is the fact. In the rectangle contained by parallels 32 deg. 45 min. and 34 deg. 20 min., and the meridians 107 deg. 30 min. and 110 deg., more than nine-tenths of the surface is of volcanic material; and from this main body there stretch two chief arms—the one going north-northeast eighty miles to Mount Taylor, and the other west-northwest, one hundred and seventy-five miles, in Arizona, to the San Francisco group of volcanoes. Its total area is more than twenty thousand and probably nearer twentyfive thousand square miles, or about half that of the State of New York. The portion embraced by Arizona is over onehalf of the whole.

An endeavor has been made by J. Richtofen, (article-a "Natural System of Volcanic Rocks," Proceedings California Academy of Sciences) to establish a correlation between the geological age and priority of volcanic rocks and their chemical and lithological nature. He considers the following to be their order of sequence, viz: propylite, andesyte, trachyte, rhyolite and basalt. Propylite and andesite are rarely seen on the Colorado plateau. The multitudinous varieties and intergradation of trachyte and rhyolite prevent ready discrimination in the field, and occasioned doubts of the validity of their separation; but with a single exception, at Truxton Spring, Arizona, basalt was everywhere seen, by members of the Wheeler expeditions, to overlie rhyolite and trachyte. Arizona may be described as one of the most marvelous portions of the American continent, equaled perhaps, but not surpassed, by the wonderful Yellowstone region, whose striking features of mountain, chasm, geyser, and strange color-tones Moran's brush has made familiar. The western Sierras can be divided into three great divisions-the parks, basins and plateau. Lying between the Rocky Mountains on the east and the Sierra Nevada on the west, the transverse chains form great basins, of which that of the Salt Lake is the chief within the bounds of the United States. The park system is found chiefly in that portion of the Rocky Mountains embraced by a part of Wyoming and the whole of Eastern Colorado, reaching down along the north-west edge of New Mexico and extending over to the eastern portion of Arizona, where, at the head of the Gila, Rio Verde, Colorado-Chiquito, Puerco and Rio Francisco, several small parks, bowl-like gems of exquisite scenery, are found. Arizona exhibits the plateau system in its greatest features. One-half of the great Colorado plateau lies within

COLORADO PLATEAU.

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its borders, occupying about two-fifths of its area. It forms an irregular triangle from the point where the Rio Colorado enters it to the north-west eastward nearly to the Rio Grande, and northward into Utah, falling away at the San Juan in Colorado and merging into the great ranges that form the Rocky Mountains. From the northern boundary line it stretches south, on the east as far as the Rio Gila, which breaks from and through its lower bench-the Mogollon. From its extreme southern point the outer edge of this massive range of almost continuous mountain trends to the north-west for nearly three degrees of latitude. Its southern and eastern point may be set down at 109 degrees of longitude. Its northern and western, within the territory of Arizona, at about 115 degrees. The Colorado plateau consists of three mountain benches, having an average altitude of from 4,000 to 6,000 feet above the sea, the surface of which is a comparative level, with occasional peaks and bluffs of strange fantastic forms and startling heights. This great formation is entered on the north by the Rio Colorado, which cuts its way westward through the mightiest of chasms and cañons. It is entered on the north-east edge by the Rio San Juan, forming a region famous now for its silver deposits, and it is also pierced by the Colorado-Chiquito, the Verde, the San Francisco, Salina, or Salt, and the upper forks of the Gila River. These rivers make more or less deep cañons and narrow valleys; the latter are adapted to stock and agriculture. The summits of the plateaux in many places furnish nutritious food for stock.

The mountain ranges of Arizona make one of its most remarkable features, rivalling even in the grandeur of their formation the wonderful cañon system which finds in the course of the Colorado, the Gila, and the Colorado-Chiquito the most magnificent of illustrations, with regard either to the mighty forces that have been and still are at work to produce them, or the amazing majesty of scenery which they display. From the Rio Grande to the Colorado the whole country presents the character of a vast upland, crossed by a succession of mountain ridges and basin-shaped valleys, interrupted by the product of recent volcanic eruptions in the form of extinct. craters, cones and streams of lava, which have overflowed and buried up the lower sedimentary rocks. The principal mountains exhibit a granite nucleus, which at certain points is exposed to view in irregular ranges, constituting the general frame-work of the country. Intermediate to these is the great table-land or mesa formation of western New Mexico and east

ern Arizona, comprising the sedimentary strata of triassic and cretaceous rocks, which spread out into broad uplands, abruptly terminated by steep mural declivities, bounding valleys of erosion, or presenting isolated buttes and fantastically castellated rocks that serve to give a peculiar aspect to the scenery. The principal foci of extinct volcanic action in Arizona is represented by the San Francisco cone, attaining an elevation of over 12,000 feet above the sea, whose alpine slopes, reaching above the water line, present in its covering of snow the chief wintry feature pertaining to this latitude. The chief ranges are the Peloncillo, the Pinaleno, the Santa Catarina, the Santa Rita, the Dragoon and the Chiricahuas, in the south-east; a low range along the north bank of the Gila, the Mogollon and the White Mountains on the east; between the Gila and Little Colorado, the Zuni Mountains, the larger portion of which lie in New Mexico; the San Francisco range and peak in the north; the several sierras that girdle in Prescott and extend north and east of that point; the Peacock, Cerbat and Hualapais ranges in the northwest; and the Castle Dome Mountain in the vicinity of Yuma. To enter into a description of these ranges-all the great physical features of Arizona-would require a volume of itself. There are many striking peaks, large and small, and isolated formations of singular massiveness and picturesque beauty. Some of them attain a great altitude.* Among these, besides the master cone-the San Francisco Mountain-are to be mentioned Mt. Graham, Mt.Wrightson, Sugar Loaf Peak, the Tucson, Picacho and Superstition mountains, Mt. Sitgreaves, the Baboquivari Peak, the Blue Peak, Mt. Turnbull, Mt. Kendricks, Thumb Butte at Prescott and Music Mountain, with others as notable. Lieutenant Ives, in the report of his famous expedition of 1854, named a peak, near the Colorado River, on the north-west, "Music Mountain,' because the regularity of the strata of which it is composed and the singular erosive work on their face give it the distinct appearance of a huge sheet of music, carved on the mountain's face by the cunning hands of the Divine composer, through the agencies of wind and water, leaving there a score that awaits only the thunderous voice of nature herself to evoke vast harmonies for the listening world.

The mountain ranges there have generally a north-west and south-east course. Long, narrow valleys lie between them. The Mogollon extends east and west. The axis of the Black Moun

*See Table of Altitudes in the Appendix.