"Geology, Stratigraphic Precambrian." . . "Geology, Stratigraphic." . . "Precambrian Geologic Period." . . "Montana" . . "Geological Survey (U.S.)," . . "Plains (Mont.)" . . "Geology Montana Sanders County." . . "Prichard-Formation." . . "Prichard Formation." . "From 570 million to 2 billion years ago" . . . . "Geology." . . "From 570 million to 5 billion years ago" . . . . . . "The Prichard Formation of the lower part of the Belt Supergroup (middle Proterozoic), near Plains, Sanders County, Montana"@en . "The Prichard Formation of the lower part of the Belt Supergroup (middle Proterozoic), near Plains, Sanders County, Montana" . . . . . . . . . . . . "The Prichard Formation of the lower part of the Belt Supergroup (Middle Proterozoic), near Plains, Sanders County, Montana" . . . . . . . . . . . . . . .