Michael Casilliano

Michael Casilliano is a geologist whose name is closely tied to The Geologic History of Fossil Butte National Monument and Fossil Basin, a National Park Service Occasional Paper published in 1975. That book, written with Paul O. McGrew, explores the geology and fossil record of Fossil Butte in southwestern Wyoming.

The publication identifies him with the Department of Geology at the University of Wyoming, which places his work in an academic and field-research setting connected to one of the American West’s most important fossil sites. His writing helped present complex geologic history in a form that could serve students, park visitors, and anyone curious about prehistoric landscapes.

Little biographical information appears to be readily available beyond that confirmed publication record, so the most reliable picture of his career comes through the work itself: careful, science-based interpretation of a remarkable fossil basin.