This app is a free resource designed to help individuals identify and better understand fossil species from the Neogene, Pennsylvanian, Ordovician, and Cretaceous of the U.S.A. It is a companion to the Digital Atlas of Ancient Life website https://www.digitalatlasofancientlife.org and was supported by grants from the National Science Foundation (NSF EF-1206757, EF-1206769, EF-1206750 and DBI-1602067, DBI-1645520) to principal investigators Dr. Bruce S. Lieberman (University of Kansas), Dr. Alycia Stigall (Ohio University), and Dr. Jonathan Hendricks (Paleontological Research Institution). This project is related to a broader natural history specimen digitization effort supported by the National Resource for Advancing the Digitization of Biodiversity Collections (ADBC) called Integrated Digitized Biocollections, or iDigBio. For additional information about this work please see the open-access paper by Hendricks, Stigall, and Lieberman (2015) in Palaeontologia Electronica.