Paleontology and geology
During the Cambrian, Maryland lay much closer to the equator than it does today. A shallow sea rose to cover the state, and sediments eroding off the land formed a sandy sea floor inhabited by trilobites, brachiopods, and other marine organisms. Limy sediments accumulated father offshore. Some of these rocks, visible in the Chesapeake & Ohio Canal National Historical Park in western Maryland, contain fossils of trilobites and conodonts.