These are sedimentary rocks of Devonian age that belong to the Unadilla Formation . The rocks around Oneonta are Unadilla Formation as well. These rocks contain ripple marks and cross-bedding that indicate deposition by streams and rivers. There are also some marine fossils preserved in these strata. Devonian age ripple marks preserved in sandstone of the Unadilla Formation.
Rivers play a key role here in two very different ways and at two very different times.
375 million years ago in the Devonian period rivers flowed here. These rivers were responsible for the deposition of the sediments upon which we are now standing, and formed the ripples and channels that we can see preserved in the rock. This river came into existence after the glaciers melted 10 thousand years ago. This modern river is not depositing sediments, rather, it is eroding down through the ancient rocks of the Unadilla Formation. Schoharie Creek is cutting the small gorge in which we are standing.