Progress report on geologic study of the Crosby and Ironton area of the Cuyuna Range, Crow Wing County, Minnesota

The detailed geology of part of the Guyana manganiferous iron-ore district was mapped during the summer and autumn of 1951. The only exposures of bedrock in or near this area are in the open-pit and underground mines where two or more layers of iron-formation and associated elastic sediments have been deformed into a complex fold system and have been intruded by large dikes. The accompanying maps and sections show the distribution of the several rock types exposed, brief descriptions of these materials, and data on the geologic structure. For the most part this structural and lithologic information has been generalized from much more detailed maps prepared in the field on scales of 30, 40, or 50 feet equal to one inch.