Jim Sansom and Ernie Lundelius

Jim Sansom (left). Ernie Lundelius (right) was the paleontologist who was called to identify the animal remains inside Inner Space Cavern.

Geologist recalls 50 years of cavern exploration

Jim Sansom was the first staff geologist for the Bridge Division of the Texas Interstate Highway System (formerly Texas Highway Department) in 1963. Little did he know that his work would lead to him being the second person to enter what we now call the Inner Space Cavern.

What did your job entail?

My boss, Horace Hoy, and I reviewed the foundations of all bridge and overpass plans across the state. We delegated drill teams to sites of concern, to help engineers to design the best foundations for the structures.

As a geologist, did you know that you might drill into a cave?

Before the core driller, Sylvan Turner, drilled the first hole into what is now called Inner Space Cavern, I told him that there was a possibility that he might drill into a small cave. He was drilling into the Balcones Fault Zone, where caves are commonly found. But I was surprised that he drilled into such a large cavern.

What was it like inside the cave?

Dark, damp, and hard to breathe in. The air was so stagnant that smoke from a match did not disperse readily and floated aimlessly in space. It was constantly a humid 72°, regardless of the weather outside.

Other than its size, what is significant about the cavern?

Dr. Ernest Lundelius has some interesting findings in his identification and dating of animal bones, many of which represent extinct animals. Dr. Jay Banner is conducting significant research about the cave’s development.

What do you do now?

I retired from the state of Texas after 33 years. Since then, I have been a consulting geologist in the central Texas area. Now, I consider myself semi-retired. I have been a part of leading tours through Inner Space Cavern many times.


Learn more about the cavern through their Inside the Aquifer Youtube playlist and the paper “Inner Space Cave: Discovery and geological and paleontological investigations.”

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