PaleontologyRegarded by many as the expert on Quaternary geology, Glen is responsible for much of the outstanding collection of Pleistocene vertebrate fossils held in the Vertebrate Paleontology Laboratory of the Museum.

TheĀ Friesenhahn Cave is one of the most important sites excavated by Glen.

TheĀ Lake Channing Ash beds were an area where Glen collected invertebrate and plant fossils.