TY - RPRT TI - Tectonic imbrication and foredeep development in the Penokean orogen, east-central Minnesota: An interpretation based on regional geophysics and the results of test-drilling. The Penokean orogeny in Minnesota and upper Michigan; a comparison of structural geology AU - D. L. Southwick AU - G. B. Morey AU - Timothy B. Holst AU - L. M. H. Carter PY - 1991 DO - 10.3133/b1904cd UR - https://pubs.usgs.gov/publication/b1904CD ID - b1904CD ER -