Called the Galapagos of the Coal Age, these 310-million-year-old cliffs preserve ecosystems inside fossilized tree stumps. Early reptiles and giant millipedes were buried when hollow trees filled with sediment. The cliffs erode so fast that new fossils tumble onto the beach every year.
Dustin M. Ramsey (Kralizec!), CC BY-SA 2.5
A forest floor frozen in time
Along the coast of Nova Scotia, the world's highest tides carve away at 15 kilometers of sea cliffs, revealing a complete world from 310 million years ago. The Joggins Fossil Cliffs are a cross-section of the Pennsylvanian subperiod, a time when tropical, swampy forests covered this landmass near the equator. These are scattered fossils, but an entire ecosystem preserved in place, leading to the site's UNESCO World Heritage designation in 2008.
The dominant plants of this "Coal Age" forest were giant, tree-like lycopsids such as Lepidodendron and Sigillaria, which grew to heights of over 30 meters. These plants had pithy, soft interiors. When they died, their outer bark often remained, leaving behind tall, hollow stumps. Periodic floods would wash sand and sediment into these hollows, instantly entombing any small animals that had taken shelter inside. The result is a form of preservation: a fossil record of forest-floor life found inside the fossil trees themselves.
The first reptiles and giant arthropods
In 1859, geologist John William Dawson found the delicate skeleton of a small animal inside a fossilized tree stump. He named it Hylonomus lyelli, meaning "Lyell's forest-dweller," in honor of his mentor, the famous geologist Charles Lyell. This creature, about 20 centimeters long, is recognized as one of the world's earliest known reptiles and the first animal known to have fully adapted to life on land. Over 190 fossil skeletons of small amphibians and reptiles have since been discovered at Joggins, many within these tree-stump traps.
The forest floor also contained giant invertebrates. Fossil trackways up to 50 centimeters wide belong to Arthropleura, a millipede-like arthropod that could grow over two meters long, making it the largest known land invertebrate of all time. These tracks show the creature swerving around obstacles on the forest floor. Other fossils include early land snails, insects like giant dragonflies, and the sprawling root systems of the lycopsid trees, known as Stigmaria. The constant erosion from the Bay of Fundy's 13-meter tides means new fossils are continuously exposed on the beach.
💡Fun Facts
Geologist Charles Lyell's study of Joggins helped convince Charles Darwin of the terrestrial origin of coal, a concept Darwin included in "On the Origin of Species".
The Bay of Fundy tides that erode the cliffs are the highest in the world, with a vertical range that can exceed 16 meters.
*Hylonomus lyelli*, discovered at Joggins, was named Nova Scotia's official provincial fossil in 2002.
It's illegal to collect fossils from the beach without a permit, but visitors often find and photograph new discoveries exposed by the tides.
