Permian Period

While Sidmouth is famous for its Triassic red cliffs, the oldest rocks in the district actually date back even further to the Permian Period. These rocks, known as the Exeter Group, consist of a mix of quartz-rich breccia, purple-brown sandstones, and reddish-brown mudstones.

1. Life on a Supercontinent: Pangea

The Permian (299 to 252 million years ago) was defined by the formation of Pangea—a single, massive supercontinent created when all of Earth's landmasses collided.

• A Desert World: Because Pangea was so large, its interior was blocked off from cooling ocean currents, creating vast, scorched deserts.

• Sidmouth’s Signature Color: The reddish-brown mudstones and sandstones we see today are the direct result of these ancient, arid conditions.

2. Permian Life: Before the Dinosaurs

Before dinosaurs dominated the Earth, the Permian was home to a diverse array of reptiles, amphibians, and insects.

• Top Predators: Creatures like the sail-backed Dimetrodon roamed the land.

• Herbivores: The spiky-backed Edaphosaurus lived alongside early groups of diversifying plants.

3. The "Great Dying": The Permian-Triassic Extinction

The Permian ended with the most catastrophic event in Earth's history: the Permian-Triassic Extinction Event.

• The Toll: This event wiped out roughly 96% of marine life and 70% of land life.

• The Cause: Scientists believe a combination of massive volcanic eruptions, climate change, and potential asteroid impacts triggered the collapse.

• The Result: By clearing out so many existing species, this extinction paved the way for the rise of the dinosaurs in the following Triassic Period.