NORTH AMERICA/Continental Interior 33 Figure 14 Cross sections of selected areas in the Continental Interior A Michigan Basin; B Illinois Basin; C Williston Basin; D Ozark Dome west to Great Plains; E Great Plains through Denver Basin to Rocky Mountains; F Ozark Dome south west through the Anadarko Basin to Wichita Mountains Denver and Anadarko basins are two of the deepest troughs in the Continental Interior (A, B, and C from Bally (1989) Phanerozoic basins of North America, in The Geology of North America, v A; E, F, and G from King (1951) The tectonics of middle North America: Princeton University Press.) Mineral Resources The Continental Interior has long been known as a rich source of metallic minerals, mostly produced from Precambrian rocks Gold has been produced from the Precambrian at Lead, South Dakota and the Porcupine and Kirkland Lake districts in Ontario, Canada The extensive Lake Superior (Michigan) copper deposits occur in Precambrian rocks and have been known for