1. Department of Geology & Geography, Mount Holyoke College, South Hadley, Massachusetts 01075, U.S.A.
2. † Special collection papers can be found online at http://www.minsocam.org/MSA/AmMin/special-collections.html.
3. Department of Geology & Geophysics, University of Wyoming, Laramie, Wyoming 82071, U.S.A.
4. Macmillan Academy, Middlesbrough, North Yorkshire, TS5 4AG, U.K.
5. University School, Shaker Heights, Ohio 44122, U.S.A.
6. Department of Geology, Colgate University, Hamilton, New York 13346, U.S.A.