Ironically, our trip to study the Geology of Western Maryland took us to many of the same kind of environments, marshes, floodplains, and beaches, as our trip to Eastern Maryland did. Only difference was that these were about 300 million years older.
Foremost among these was the Sideling Hill road cut and exhibit center. This exposure, a colossus among road cuts, was created during the late 1980s to allow Interstate 68 to pass through Sideling Hill, which had previously been a substantial obstacle. Happily, the State of Maryland grasped the educational potential of this unique locality and created an effective interpretive center there. Center volunteer Dale Shelton provided ELT students with an orientation, then led them onto the huge outcrop. The sandstones, shales, and lignites exposed in the cuts record the presence of the marshes and rivers in which they were deposited. Their folded structure records the later collision of North America and Gondwana to form the Appalachians.
Leaving the ancient stream deposits of Sideling Hill, we hit the beach at nearby Sandy Mile, a conspicuous outcrop of the Oriskany Sandstone. This rock unit was deposited as a sandy beach. The brachiopod shells that once marked its strand lines are now preserved as voids in the clean white sandstone. A short walk away, the Keyser Limestone presented a marine depositional environment dominated by the remains of shelled organisms like ostracodes and crinoids.