Minnesota Geological Survey Report of Investigations RI-62. Petrology and PGE Potential of the Greenwood Lake Intrusion, Central Duluth Complex, Lake County, Minnesota. James D. Miller, Jr., 2004 The pdf report should be viewed using Acrobat Reader 4.0 or higher for best results. If necessary, download this file as binary, not ASCII format. Also available as a printed report; contact the MGS Map Sales office at 612-627-4780, ex. 238 for price and availability.