The black and bottomless pool gleams in the shining rock—a sinister paradox, to a fanciful mind. To any man of natural piety this pool, this place, this silence, would suggest reverence, even fear. But I’m an apostate Presbyterian from a long-ago Pennsylvania: I shuck my clothes, jump in and touch bottom only ten feet down. Bedrock bottom, as I’d expected, and if any Grendels dwell in this inky pool they’re not inclined to reveal themselves today.

We return to the Aravaipa. Halfway back to camp and the canyon entrance we pause to inspect a sycamore that seems to be embracing a boulder. The trunk of the tree has grown around the rock. Feeling the tree for better understanding, I hear a clatter of loose stones, look up, and see six, seven, eight bighorn sheep perched on the rimrock a hundred feet above us. Three rams, five ewes. They are browsing at the local salad bar—brittlebush, desert holly, bursage and jojoba—aware of us but not alarmed. We watch them for a long time as they move casually along the rim and up a talus slope beyond, eating as they go, halting now and then to stare back at the humans staring up at them.

Once, years before, I had glimpsed a mountain lion in this canyon, following me through the twilight. It was the only mountain lion I had ever seen, so far, in the wild. I stopped, the big cat stopped, we peered at each other through the gloom. Mutual curiosity: I felt more wonder than fear. After a minute, or perhaps it was five minutes, I made a move to turn. The lion leaped up into the rocks and melted away.

We see no mountain lions this evening. Nor any of the local deer, either Sonoran whitetail or the desert mule deer, although the little heart-shaped tracks of the former are apparent in the sand. Javelina, or peccary, too, reside in this area; piglike animals with tusks, oversized heads and tapering bodies, they roam the slopes and gulches in family bands (like the Apaches), living on roots, tubers, the innards of barrel cactus, on grubs, insects and carrion. Omnivorous, like us, and equally playful, if not so dangerous. Any desert canyon with permanent water, like Aravaipa, will be as full of life as it is beautiful.

We stumble homeward over the stones and through the anklebone-chilling water. The winter day seems alarmingly short; it is.

We reach the mouth of the canyon and the old trail uphill to the roadhead in time to see the first stars come out. Barely in time. Nightfall is quick in this arid climate and the air feels already cold. But we have earned enough memories, stored enough mental-emotional images in our heads, from one brief day in Aravaipa Canyon, to enrich the urban days to come. As Thoreau found a universe in the woods around Concord, any person whose senses are alive can make a world of any natural place, however limited it might seem, on this subtle planet of ours.