David Kohls discovered the fossil of a cockroach that lived 49 million years ago. (Claudia Kohls)

Over the course of two decades, David Kohls, an amateur paleontologist based in Battlement Mesa, Colo., has given tens of thousands of fossils — of insects and flora — to the Smithsonian Institution and the University of Colorado. Kohls, 77, a retired community college administrator, has been searching for fossils in Colorado for 20 years. An ancient cockroach, thought to be about 49 million years old, was recently discovered in his collection and named after him (Ectobius kohlsi).

We talked to Kohls about his passion for fossils, and why he decided to give away his loot.

What inspired your interest in fossils?

I grew up in Kansas, near a place called Elmo, the site of some of the most spectacular, large insect fossils ever found. There was talk around the dinner table about those fantastic fossils. Maybe subliminally it just stuck with me.

How did you get started collecting?

I was working as an administrator at the campus of Colorado Mountain College in Rifle and hired a scientist named Bob Koper. To keep my own teaching certificate current, I took his geology class in 1991. During a field trip I found my first fossil — little worm burrows and some shells. That lit a fire in me that just would not quit.

How did you pursue this passion?

I started searching locally for fossils and soon found out that I had some of the greatest resources for fossil insects and materials in the world nearby. It was like living right in the middle of a sugar bowl, and you’re the ant.

So I looked at geological maps and got permission to access places where I thought fossils would be. I established 11 collecting spots and gave them all names, such as Claudia’s place, after my wife. The main area was basically a lake bottom that had accumulated over time and formed a 1,000-foot-thick wall. I’d stand there at the face and pick off naturally weathered, thin pieces of shale, as small as a fingernail or as big as a dinner plate. Sometimes I’d collect 300 to 500 pieces. I spent just about all my free time doing it.

How many fossils did you collect altogether and where are they now?

I have about 30,000 pieces at the Smithsonian, and about 48,000 pieces at the University of Colorado. But on each piece, there could be four specimens. So if you do the math, that’s more than a quarter of a million individual specimens.

Did you get any training or help?

All of these things were new, self-taught and self-funded. But I did have some guidance. I found out that paleoentomologists are more than willing to help an amateur such as myself.

One thing that has been said in favor of these collections is that they’re unbiased. Everything I came across — plant or insect — I kept, so the science people can now go back and get a better picture of how things were 50 million years ago. I think there will be multiple PhD dissertations and master’s papers written, and discoveries made.

One discovery is an ancient cockroach which was named after you. Were you pleased?

Of course, I’m honored that someone would be so kind as to name anything at all after me. But the most important thing is the fact that people are studying the material and making identifications.

Why did you donate your collection rather than keep or sell it?

I never thought about selling it; that was the last thing I ever wanted to happen. I felt I had to donate the collection to science so someone could do something with it. That kept me moving.

This is an edited version of a story that appeared originally in New Scientist .