Lower Proterozoic Volcanic Rocks and Their Setting in the Southern Lake Superior District Reprinted from Geological Society of America Memoir 160. Bedrock Geology Precambrian Bedrock Data and Resources MP83-4 Lower Proterozoic Volcanic Rocks and Their Setting in the Southern Lake Superior District Greenberg, J.K.; Brown, B.A.; 1983 Report: p. 67-84 Download Related Collections Miscellaneous Paper View Miscellaneous Paper