"From 425 to 570 million years ago" . . . . "Charts, diagrams, etc"@en . . . . . . . . . . . . . . "Stratigraphic framework of Cambrian and Ordovician rocks in the Appalachian Basin from Sequatchie County, Tennessee, through eastern Kentucky, to Mingo County, West Virginia"@en . . . . "Cambrian and Ordovician rocks in the Appalachian Basin from Sequatchie County, Tennessee, through eastern Kentucky, to Mingo County, West Virginia"@en . . . . "Appalachian Basin" . . . .