Fossils – layer by layer
By 350 million years ago, Laurentia had drifted to near the equator, the desert had been replaced by a hot, damp, fly-infested tropical climate. The sea moved up and down, giving differing coastal conditions, each identified by the creatures that lived in it and became preserved as fossils. In swamp forests grew lush vegetation forming peat then coal. The tree roots occur in fossil soil below the coal. Flooding tropical seas killed the forest burying it with marine muds and coral reefs with rich marine life became limestone. The sea retreated leaving lagoons with shells and plant debris in muds and silts. Rivers filled the lagoons building sand and silt deltas into the sea. On this new land coal forests grew; and so the cycle started all over again.
In East Lothian collect fossils at Barns Ness – White Sands – Catcraig, here limestones and shales are full of corals and shells. Pictures on the noticeboards help you to identify them. Also try Kilspindie, between Aberlady and Gosford, or Cove, or Burnmouth.