A bed of chert in a field near the village of Rhynie in Aberdeenshire, with a second unit at Windyfield about 700 metres away, formed when a hot spring flooded an early Devonian wetland with silica and set everything in it at once. It is about 410 million years old, which puts it at the beginning of life on land, and the preservation goes down to individual cell walls: stomata can be counted on the plants, lignin has been detected in them, and the book lungs of trigonotarbid arachnids can be seen in section, with fungal threads running into plant tissue as decomposers and as partners. The bed itself lies under at least a metre of overburden in private farmland and there is nothing to see at the surface, so this is a pin for the ground that changed what we know, not a place to dig.
The oldest land plants and land animals, preserved cell by cell · Early Devonian, ~410 mya
This ground is protected. Photograph it, record it, leave it where it lies. On US federal land the Paleontological Resources Preservation Act 2009 makes collecting vertebrate fossils an offence, and penalties are real.
United Kingdom
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