limestone cannot be so very old.  In comparatively recent times an earthquake or some seismic disturbance or some other natural force caused a spring of water to burst from the slope above the gorge.  It ran down, of course, over the rim.  The lime salt in the water was deposited, and year by year and age by age advanced toward the opposite side until a bridge crossed the gorge.  The swift stream at the bottom kept the opening clear under the bridge.

A winding trail led deep down on the lower side of this wonderful natural span.  It showed the cliffs of limestone, porous, craggy, broken, chalky.  At the bottom the gorge was full of tremendous boulders, water-worn ledges, sycamore and juniper trees, red and yellow flowers, and dark, beautiful green pools.  I espied tiny gray frogs, reminding me of those I found in the gulches of the Grand Canyon.  Many huge black beetles, some alive, but most of them dead, lined the wet borders of the pools.  A species of fish that resembled mullet lay in the shadow of the rocks.

From underneath the Natural Bridge showed to advantage, and if not magnificent like the grand Nonnezoshe of Utah, it was at least striking and beautiful.  It had a rounded ceiling colored gray, yellow, green, bronze, purple, white, making a crude and scalloped mosaic.  Water dripped from it like a rain of heavy scattered drops.  The left side was dryest and large, dark caves opened up, one above the other, the upper being so high that it was dangerous to attempt reaching it.  The right side was slippery and wet.  All rocks were thickly encrusted with lime salt.  Doyle told us that any object left under the ceaseless drip, drip of the lime water would soon become encrusted, and heavy as stone.  The upper opening of the arch was much higher and smaller than the lower.  Any noise gave forth strange and sepulchral echoes.  Romer certainly made the welkin ring.  A streak of sunlight shone through a small hole in the thinnest part of the roof.  Doyle pointed out the high cave where Indians had once lived, showing the markings of their fire.  Also he told a story of Apaches being driven into the highest cave from which they had never escaped.  This tale was manifestly to Romer’s liking and I had to use force to keep him from risking his neck.  A very strong breeze blew under the arch.  When we rolled a boulder into the large, dark pool it gave forth a hollow boom, boom, boom, growing hollower the deeper it went.  I tried to interest Romer in some bat nests in crevices high up, but the boy wanted to roll stones and fish for the mullet.  When we climbed out and were once more on a level I asked him what he thought of the place.  “Some hole—­I’ll say!” he panted, breathlessly.

The rancher told me that the summer rains began there about July, and the snows about the first of the year.  Snow never lay long on the lower slopes.  Apaches had lived there forty years ago and had cultivated the soil.  There was gold in the mountains of the Four Peaks Range.  In this sheltered nook the weather was never severely cold or hot; and I judged from the quaint talk of the rancher’s wife that life there was always afternoon.