The walls bristle with spiky rock gardens of formidable desert vegetation. Most prominent is the giant saguaro cactus, growing five to fifty feet tall out of crevices in the stone you might think could barely lodge a flower. The barrel cactus, with its pink fish-hook thorns, thrives here on the sunny side; and clusters of hedgehog cactus, and prickly pear with names like clockface and cows-tongue, have wedged roots into the rock. Since most of the wall is vertical, parallel to gravity, these plants grow first outward then upward, forming right-angled bends near the base. It looks difficult but they do it. They like it here.

Also present are tangles of buckhorn, staghorn, chainfruit and teddybear cholla; the teddybear cholla is a cactus so thick with spines it glistens under the sun as if covered with fur. From more comfortable niches in the rock grow plants like the sotol, a thing with sawtooth leaves and a flower stalk ten feet tall. The agave, a type of lily, is even bigger, and its leaves are long, rigid, pointed like bayonets. Near the summit of the cliffs, where the moisture is insufficient to support cactus, we see gray-green streaks of lichen clinging to the stone like a mold.

The prospect at streamside is conventionally sylvan, restful to desertweary eyes. Great cottonwoods and sycamores shade the creek’s stony shores; when we’re not wading in water we’re wading through a crashing autumn debris of green-gold cottonwood and dusty-red sycamore leaves. Other trees flourish here—willow, salt cedar, alder, desert hackberry and a kind of wild walnut. Cracked with stones, the nuts yield a sweet but frugal meat. At the water’s edge is a nearly continuous growth of peppery-flavored watercress. The stagnant pools are full of algae; and small pale frogs, treefrogs and leopard frogs leap from the bank at our approach and dive into the water; they swim for the deeps with kicking legs, quick breaststrokes.

We pass shadowy, intriguing side canyons with names like Painted Cave (ancient pictographs), Iceberg (where the sun seldom shines) and Virgus (named in honor of himself by an early settler in the area). At midday we enter a further side canyon, one called Horsecamp, and linger here for a lunch of bread, cheese and water. We contemplate what appears to be a bottomless pool.

The water in this pool has a dark clarity, like smoked glass, transparent but obscure. We see a waterlogged branch six feet down resting on a ledge but cannot see to the bottom. The water feels intensely cold to hand and foot; a few tadpoles have attached themselves to the stony rim of the pool just beneath the surface of the water. They are sluggish, barely animate. One waterbug, the kind called boatman, propels itself with limp oars down toward darkness when I extend my hand toward it.

Above the pool is a thirty-foot bluff of sheer, vesiculated, fine-grained, monolithic gray rock with a glossy chute carved down its face. Flash floods, pouring down that chute with driving force, must have drilled this basin in the rock below. The process would require a generous allowance of time—ten thousand, twenty thousand years—give or take a few thousand. Only a trickle of water from a ring of seeps enters the pool now, on this hot still blazing day in December. Feels like 80ºF; a month from now it may be freezing; in June 110º. In the silence I hear the rasping chant of locusts—that universal lament for mortality and time—here in this canyon where winter seldom comes.