Argyrosaurus femur found in February, 1924 during the Captain Marshall Field Expedition by C. Harold Riggs, son of expedition leader Elmer Riggs in the San Bernardo Hills of Argentina. The Marshall Field Expedition, undertaken by the Field Museum of Natural History in Chicago, Illinois, was a paleontological expedition with the goal of finding fossils of South American Cenozoic mammals.

- Image ID: M9GK7R