A world frozen in silica
In a small field near the Scottish village of Rhynie lies evidence of one of the planet's earliest and most complete terrestrial ecosystems. This is not a site of grand fossilized bones, but a microscopic world locked inside a flint-like rock called chert. Around 410 million years ago, during the Early Devonian period, this area was a volcanic area of geysers and hot springs, similar to modern-day Yellowstone. These springs periodically overflowed, flooding the surrounding terrain with silica-rich water that rapidly hardened, preserving everything it touched with astonishing fidelity.
The Rhynie chert, as the deposit is known, captured an entire community of organisms in three dimensions, right down to their individual cells. It contains the oldest definitive fossils of land plants like Rhynia and Aglaophyton, which stood no more than 20 centimeters tall. Fungi, algae, and lichens are also present, some showing symbiotic relationships with the plants. But among the miniature forests, a drama was unfolding between the first creatures to truly conquer the land. The chert holds many arthropods, including the oldest known insect, a springtail-like creature named Rhyniella praecursor. It also holds its potential predators.