If you've ever visited Spring Lake, you probably explored aboard a glass- bottom boat. Since 1945, the boat ride has been a quintessential San Marcos activity. This fall The Meadows Center for Water and the Environment is also offering kayak trips. I jump at the chance, making a reservation months in advance.

On a beautiful fall morning, near the headwaters of the San Marcos River, over 200 springs gurgle on the bottom of the lake. They look like sandy craters. Because the lake is spring fed, the water is crystal clear. I glide over the surface. I can see all the way to the bottom as I peer over the edge of the kayak. It is mesmerizing.

At one of the larger springs, called Cream of Wheat, white sand appears to bubble up from the depths. Under pressure, the water is expelled from the Edwards Aquifer, the rocky subterranean place where water is stored. Springs are common in this part of Texas and along with limestone caves, disappearing rivers, and sinkholes, they make up an ecosystem known as karst.

Early morning storm clouds descend on San Marcos, Texas. The wind begins blowing, rattling maps and poster board-sized photographs that are being loaded into the van. A handful of geologists, biologists, and cavers huddle nearby, running to their cars now and then to gather additional layers as the temperature drops into the low fifties.

It is field trip day, part of the 2021 National Cave & Karst Management Symposium. This is the day I have been dreaming about for months. . . really. The trip is being led by Dr. Nico Hauwert and is titled "Finding Caves in North Hays County: Recognition of Caves in an Environment Of Widespread Filling."

I watch as caving equipment is placed in the van. Helmets. Rope. Okay, I have been obsessed with subterranean ecology for three-and-a-half years. I have visited many caves, show caves with lit pathways and staircases. I have been searching for caves on my own property. But I am terrified of entering a wild cave. I think I am claustrophobic. I have a fear of heights. I am nearly fifty years old and not in the best shape of my life. Despite my racing heart, I secretly hope this group of fearless explorers will finally get me into a wild cave.