| [var. Carbonate-rich Apatite] Mahoney, J. B., K. Havholm, A. Runkel & R. Hooper (1997) Late Cambrian shelf sedimentation, Upper Mississippi Valley, Wisconsin and Minnesota: in Mudrey, M. edited, Guidebook to field trips in Wisconsin and adjacent areas of Minnesota, 31st Annual Meeting of the North-Central Section, Geological Society of America, Madison, Wisconsin, p. 51-65. |
Colfax Sandstone Quarry, Dunn County, Wisconsin, USA