Coal miners posing with the fossilized tree stump in Wilkes-Barre, Pennsylvania, 1918. Photo by J. Horgan, Jr.

In 1918, a group of coal miners working in Wilkes-Barre, Pennsylvania, made a remarkable discovery while deep inside a coal seam. They uncovered a large, well-preserved fossilized tree stump with its root system still intact.

Photographer J. Horgan, Jr. captured the moment as the miners posed proudly around the ancient stump inside the dark mine tunnel. The image has since become one of the most iconic photographs illustrating the prehistoric origins of coal.

A Literal Piece of Prehistory

The stump dates back to the Carboniferous Period, approximately 300 to 360 million years ago. At that time, what is now northeastern Pennsylvania was a vast, swampy tropical forest. When these ancient trees died and were buried under sediment, heat and pressure slowly transformed the plant material into coal. In rare cases, structures like this stump were preserved well enough to survive as recognizable fossils.

Similar fossilized stumps had been found in the same mining region before, but the 1918 discovery — beautifully documented in this photograph — remains one of the most famous.

Why This Image Still Fascinates Us

This photo makes the term “fossil fuel” feel incredibly real. The very coal these men were mining was once part of a living forest that existed long before the dinosaurs. It creates a powerful connection between early 20th-century industrial workers and Earth’s deep geological past.