of both Santo Domingo and Sonoyta, besides a quarter-load of hay and grain, set out on the Old Yuma Trail under an arrangement with Don Bartolo to deliver water and feed in Tule Pass (sixty-odd miles away) by the third evening; next day the four-mule light wagon and the four saddle animals of the expedition were on the road betimes. Crossing the sandwash of Rio Sonoyta -a channel broad enough for the Ohio, deep enough for the Schuylkill, but dust-dry from bank to bank-the way meandered over a cactus-dotted plain simulating a vast alluvial deposit but revealing its origin. by sheet flood carving in occasional projecting bosses of granite; passing monument 172, it swung a few yards north of the boundary to touch at Quitobaquito-the Papago village with five centuries behind it. and two adobe houses besides a half-dozen native huts within it. Here the entire white population (Mr. M. G. Levy, merchant, mine-owner, justice of the peace, and deputy sheriff) was avidly hospitable, the native residents. attentive, as became the unusualness of the event; and the side-barrels and half-dozen canteens of the outfit were soon filled with the slightly alkaline yet palatable and wholesome water from the spring. Quitobaquito lies amid the southeasternmost foothills of a sierra bearing the name of spring and village; a dozen miles away the range divides, a spur setting off southward to form Cerro Salado (or Sierra de la Salada), and the trail veers partly to avoid this spur, partly to touch the last water" near its tip.

Beyond Quitobaquito the ancient trail grows impressive. True, the narrow

stock-path followed by the wagons is in large part new; but, as well seen from the crest of Cerro Huerfano, the new track diverges from the old only because the old was so deep that it has become a storm-cut arroya-indeed for miles Rio Sonoyta abandons the ancient sandwash during its brief spurts of activity to convert the wheel-worn way into a flood-channel. Prehistoric sites and relics of the early stone age are sparsely scattered over the plain; the ruins of a Mexican rancho, with well and corral and acequias, lie three miles west of Quitobaquito; and there is an abandoned ganadero (stock ranch) at the "last water" five miles beyond, known commonly as "Agua Dulce" from the

alkaline sweetness of the water, properly as "Agua Salada" from its salinity. The "agua" is merely the small residuum of underflow and local seepage brought to the surface of the Sonoyta sandwash by impervious ledges of Cerro Salado in their subterranean extension across the valley; and the banks and bottom are encrusted with frost-like efflorescences of mineral salts. The water is fair for stock, just potable for men; it is a resort for half-wild cattle and horses and burros ranging the sierras and valleys. for twenty miles beyond; but the latest sign is that of Don Bartolo's outfit, whose casks and kegs were filled twentyfour hours earlier. Here we pitch a tentless camp, with the first graves of the Old Yuma Trail on a low spur hard by ; the sky is clear, though the air is heavy and warm; and Coyote (the Wise One of Papago lore) creeps near to sing his rain-song-a sleep-breaking wail well understood of the vaqueros.

THE SUMP OF THE SONOYTA

The first faint dawn of the 17th is ushered by a slow sprinkle from low clouds, forming a fog-bank half way up the Cerro, but so light overhead that the brighter stars glimmer through; and blankets are hurriedly rolled and loaded, breakfast is bolted, and the outfit is under way in the gray twilight. With sunrise the floating fogs fade, revealing the entire salt-pan in which Rio Sonoyta comes to an end—a basin of a score square miles, bounded on the north by Cerro Salado and its footslopes, on the west by minor ranges running down from Sierra Pinecate, and on the southeast by a sheet flood slope studded with volcanic buttes and mesas; while the old valley opening southwestward to the Gulf stops at a dam of hundred-foot dunes marking the margin of the Red Desert-a seaborn tide of sand slowly engulfing the lowlands of Sonora from Rio Colorado to Lobos Point. This is the "sink "

of the Sonoyta in the pioneers' vernacular, its evaporating vat in physical fact; after freshets it is lake or morass according to the volume of the flood, and then bottomless mire for weeks; now it is a Titan-patterned carpet of red, white, yellow, and black efflorescences, relieved by the greens of salt-enduring shrubbery on higher spots. On the hard-baked surface-crust the hoofs drum and the wheels rumble with a hollow reverberation more disturbing to animals than to men-albeit reminders to these of tragedies galore in the treacherous sump. A herd of wild burros see or scent the leading horseman from afar, and after deer-like stamps and snorts and other signals gather in a bunch, with dams and foals in the lead and males in the rear, to skim with amazing swiftness--recalling the wild asses of Arabiadown the rocky slopes and over the resounding playa obliquely across the trail toward the impassable sand-dunes ; while an occasional band of half-wild horses may be glimpsed lurking behind mesquite clumps or scurrying for more distant shelter.

The trail leaves the Sonoyta basin about longitude 113° 10′, and ten miles south of the boundary; thence it wanders northwestward over rocky footslopes, bending slightly to avoid isolated buttes and curving more sharply to cross arroyos, for a dozen miles--to an imperceptible divide and the invisible frontier, where it enters a typical valley-plain of southwestern Arizona. Just outside the basin we overtake the supply outfit (which should have been thirty miles further on), and learn of the broken queen bolt and the long night ride by the Mexican to replace it, while the Indian staid by the stock; and we foregather to revise plans, swallowing apprehensions and a cold bite as the rare clouds of Papagueria gather to break in noonday. showers and dispel the darkest danger of the desert. After arranging a rendezvous where galleta grass may be

found (for all stock trails are now left behind), the lighter outfit pushes on to outspan in sight of monument 178 (longitude 113° 20′)-the first "dry" camp. on the Old Trail. Here sign of antelope and deer are seen, and the galleta is recovering slowly from the over-pasturage of the mid-century; Mr. Gill finds a curious aboriginal cache in a cavern of the volcanic butte on which the monument stands; and showers come and go throughout the night.

ACROSS PLAYAS AND MALPAIS

The second morning from Santo Domingo is cool and cloudy; blankets and saddles are stiff with the wet, the animals fractious; but three miles of smooth going and a rising sun bring comfort. with the passage through a congeries of granite picachos rising abruptly from the level plain-and the pass is a gateway into Tule Desert. The first quarter of this expanse alternates between bare playa and a lax thicket of creosote (Larrea) growing in extraordinary luxuriance (clumps twelve feet high and branches fifteen feet long are common), while the silty floor is riven every few rods by giant shrinkage-cracks, often a foot or more wide and a yard or two deep. Fortunately the showers here have been light; yet the alkaline silt is tenacious mud, fetlock-deep for the mules and twice felloe-deep for the wagons. The next fraction of the valley is a tongue of the Red Desert, reaching in by the western end of Sierra Pinecate and stretching a dozen miles northward to lap the base of parti-colored Sierra Pinta; for five miles the old trail (which was lost in the playas) reappears here and there as a deep-worn way, partly filled and often obliterated by drifting sands; and the dead drag is the more dispiriting for the steady upgrade toward the malpais belt dividing Tule Valley.

This malpais-theme of many a trav

eler's tale-forms a notable feature of the old route. It is a vast sheet of black lava stretching toward Sierra Pinta from a group of craters (and probably unseen fissures as well) a few furlongs or miles south of the roadway; but while so youthful, in geologic sense, that the principal lines and lobes of flowage and the rugged scarps of the margins remain distinct, the surface is weathered into a pavement of pebbles bedded below in light yellow sand but polished above by a "desert varnish" of remarkable brilliance; and the pebbles are set so close that the varnished surfaces form a nearly continuous mirror miles in extent, reflecting light and heat with painful intensity. The malpais belt forms a low mesa on which an occasional scrubby mesquite or saguaro (Cereus giganteus) or pitahaya (Cereus engelmannii) has found lodgment; it affords fine views of the Painted Range on the north, of the serrate crests and pointed peaks brought out by the afternoon sun in Tule Mountains, and especially of Sierra Pinecate, now falling into the rear on the left; and the last view serves to rectify the reports of the pioneers by showing that Pinecate is not a crater but a range, that the malpais stops miles short of its nearer base, and that it rises from the Red Desert quite like other ranges of western Sonora, though to a loftier height than any neighbor. Through the polished pavement of black malpais the old trail is distinct as a line on a map; the larger pebbles and boulders have been thrown out of the way of wheels by generations of travelers, while the smaller are ground into the ashen sand; and at intervals not exceeding a few hundred rods the bordering pavement is broken by crossshape pebble-piles marking the journey's end now of a youth, again of mother and child, elsewhere of two or three adult companions, but more commonly of the single traveler, as told vaguely by the size and form of the heap-all

grim reminders that among the pioneers the malpais was a favorite place for dying.

A DESERT STORM

The stock are breathed on the nearer edge of the malpais, amid passing showers; then pushed on (the lighter outfit gaining rapidly) toward Tule Pass. Meantime the clouds about the southeastern sub-range of Sierra Tule grow dense, while those on neighboring crests lighten; then the cloud-mass veils the sub-sierra to its base, and half an hour later sets slowly northeastward over Tule Valley toward the trail, so slowly that both outfits are across the malpais and in the western half of the Red Desert tongue before the tempest strikes.

A typical desert storm (though of exceptional severity) was this, and instructive in every aspect. While among the peaks the cloud-bank was about

3,000 feet high and flattened domeshape above, five or six miles in diameter at two-thirds of the height, and three miles across at the level of the plain (the rain-lines seen in the lower third converging from both sides); and these proportions seemed to be maintained, save for slight flattening, as the mass drifted into the valley and grew in size. It was most orderly in behavior; its rate of advance-after its clinging hold on the sieria broke-was eight or ten miles an hour; and the roar of rain and wind on drifted sand and scattered mesquites was audible half an hour, ominous for half as long, before the storm was actually at hand. Steadily the rim of cloud-bank pushed forward, passed overhead, and eclipsed the entire heavens save the northeastern eighth; light sprinkles fell from it directly downward through still air at first, but grew heavier as they caught