Illustrations from a nineteenth-century geology textbook show typical marine shellfish fossils of Devonian age, a time period running from 419 to 369 million years ago. That’s the age of almost all the rocks here in the Catskills. Those fossils speak to geologists of a time when all of our region lay beneath the waves of a shallow sea, sometimes called the Catskill Sea.
You can see good black shales on Glasco Turnpike near Mt. Marion. Other black shale strata are seen along Route 209, north of Kingston. Visit either of these locations and see the dark color and view the laminations. Uniformitarianist geologists find sediments resembling these at the bottoms of today’s deep seas.
The best place for you to visit limestones is along Rte. 9W where it passes through the Kingston malls. Almost all the rocks there are limestones. You can see more limestones along Rte. 32, just north of Saugerties.
By the midnight of this awful night the storms had passed, and things had settled down. Where there had been colorful marine meadow, now there was the barren desolation of a fresh 10-inch thick deposit of coarse sediment. Few seafloor creatures were still alive; many had been broken up into a shell hash. As the moon rose over the dark sea floor, the last grains of the finer, lighter sediments were falling out of suspension like a marine dust. The new deposit was settling and compacting under its own weight. It was beginning a long process that would very slowly turn it into limestone. That limestone is still there, exposed along Rte. 9W.
To geologists, there is a simple question. How did these waterfalls, with their hazards, come into existence? Haven’t waterfalls just always been there? Well no they haven’t; they were brought into existence by geological processes. We just have to be observant enough to figure out those processes.
Why is it that when a large group of mammoth bones are found, a disproportionate number of them are males?
Make your way to Rte. 214 and head north until you reach Stony Clove Gap. That’s a very sizable boulder at the Devil’s Tombstone Campground in the eastern Catskills.
Good hiking weather is coming up soon enough. Maybe you should climb Overlook and see the geology up there for yourself.
It’s an important unit of time here in the Catskills.
Our intrepid local geology columnists examine signs of glaciers at North Lake’s Site 151.