As with all the fossil collections at Field Museum, the Fossil Fish Collection was begun through the purchase of the Wards Natural Science Establishment exhibit at the Columbian Exposition of 1894. The Fossil Fish Collection also received specimens from the transfer of the University of Chicago’s Walker Museum collection in 1947. Fossil Fishes was expanded though collecting parties led by Robert Denison in the late 1940s through the mid-1960s, by Rainier Zangerl in the 1950s to the 1970s, and later by Lance Grande from the mid 1980s to the present. Denison worked in Paleozoic rocks with a primary focus on the Devonian. He worked in the Western US, Canada, and in Europe. Rainier Zangerl focused on fishes from the Pennsylvanian black shales of Illinois and Indiana. Lance Grande’s fieldwork has been primarliy in the Eocene Green River Formation of Wyoming. He has also worked in the Cretaceous of Mexico.