CAVING TEXAS

I’M PERCHED ON THE STONY LIP OF A GAPING HOLE IN THE PRICKLY CHIHUAHUAN DESERT SCRUBLANDS NEAR DEL RIO, checking and rechecking the rappelling harness buckled snugly around my waist. Forty-five feet below, four fellow cavers stand atop a bus-sized mound of bat guano, blinking up at me as I lean back for the drop into the shadows of Punkin Cave.

I’m afraid of heights, and the thought of plummeting four stories into the bowels of the earth is making my hands shake. I squeeze my eyes shut for a moment, trust the cavers who are belaying me, and lower myself slowly into the abyss. For the next few minutes I dangle in midair, scuttling down the rope like a spider on a silken thread.

More than 5,600 documented caves twist and turn their way through the limestone and gypsum bedrock that comprises much of Texas’ underbelly. That’s a lot by any standard, but it’s even more impressive considering most of the state is privately owned land, where caves haven’t been investigated or mapped. Many of the known caves are clustered along the Balcones Fault Zone, a crack in the earth’s surface that curves