| 2005-2013 | Associate Dean of the Faculty, The Colorado College |
| 1997- | Professor of Geology, The Colorado College |
| 1988-1997 | Associate Professor of Geology, The Colorado College |
| 1989-90 | Associate Professor of Geology, Temple University, Japan |
| 1981-88 | Assistant Professor of Geology, The Colorado College |
| 1981, 82, 85 | Summer Director/Asst.Dir.ACM Geology in the Rockies |
| 1980-81 | Instructor of Geology, The Colorado College |
| 1979 | Teaching Assistant in Geology, Stanford University |
| 1975 Summer | House painting |
| 1972,73,74 Summer | Construction labor |
| 1971 Summer | Lifeguard |
