What (and where) are the oldest and the youngest rocks in West Virginia?
Rocks exposed at the surface in West Virginia range in age from Precambrian (about 570 million years old) to Permo-Pennsylvanian (about 280 to 285 million years old). The oldest bedrock (rock in place) exposed at the surface is found in the southeastern tip of Jefferson County. These rocks, of the Catoctin Formation, are approximately 570 million years old (Precambrian age) and consist of metamorphosed basalt lava flows. It is possible that some rock fragments even older than this (such as granites) were transported in glacial till and occur in Ohio River outwash, but these are not native to West Virginia. Other than Eocene intrusives in Pendleton County (see next question), the youngest bedrock in the State is found in the Pittsburgh-Huntington Synclinorium (the Dunkard Basin), a broad basin in western West Virginia, southwestern Pennsylvania, and southeastern Ohio. In West Virginia, the Dunkard Basin extends from the northern panhandle southward down the Ohio River to about I-64 and
