Round Top Geology

Round Top Geology. Chesapeake and Ohio Canal National Historical Park. The layers of red sandstone, siltstone, shale and limestone beneath the limekilns on the other side of the canal are like pages in a book to geologists. These folded, even rock layers indicate that millions of years ago this area was covered by a shallow sea. As the waters swelled and retreated, due to climatic change and tectonic plate movement, the colorful layers of sedimentary rock were exposed., The rocks also tell a story of a violent collision between the North American and African tectonic plates over 240 million years ago, the same collision that formed the Appalachian mountain chain The force of the impact caused the rocks to fold and fault, creating the anticline or upward arch in the rock layers visible under the kilns., (caption) , Canal engineers discovered high calcium limestone in Round Top during construction in the 1830s. By 1838 Round Top Cement Company began mining operations here. This photograph shows an anticline after the layers of limestone were removed., Down the towpath 200 yards to your right is Devil’s Eyebrow, a hollow that formed when the soft, lower layers of calcium-rich rock eroded leaving the more resistant harder layers of the anticline intact. . This historical marker was erected by National Park Service, U.S. Department of the Interior. It is Near Hancock in Washington County Maryland