some of the rocks exposed in the park date to over one billion years in age, making them among the oldest in virginia. bedrock in the park includes grenville-age granitic basement rocks (1.2–1.0 billion years old) and a cover sequence of metamorphosed neoproterozoic (570–550 million years old) sedimentary and volcanic rocks of the swift run and catoctin formations. columns of catoctin formation metamorphosed basalt can be seen at compton peak. clastic rocks of the chilhowee group are of early cambrian age (542–520 million years old). quaternary surficial deposits are common and cover much of the bedrock throughout the park.