Black shales on Rt. 209

The evolution of the trees got underway for real during the middle Devonian time, about 380 million years ago. Many of the earliest forests grew right here in the Catskills region. But the evolution of the trees was not an unblemished positive. Trees helped create deep soils which, when they eroded, provided excessive nutrients to the nearby seas. The result may have been an oxygen-depleted “poison sea.”