This chapter proposes a fresh approach, based on the notion of epistemological culture, to the seminal work of Cuvier on mammal paleontology. It recounts the story of the reconstruction of Tertiary mammals on the basis of scattered and incomplete fossils found in gypsum quarries around Paris. In the process of transforming a technical problem of fossil osteology into a new research strategy, Cuvier mobilized three different epistemological cultures: a museum culture, developed by collectors, curators, and taxonomers; late Newtonianism, which the Parisian physicists of his time promoted; and antiquarianism practiced by historians who claimed to restore vestiges of the past to their authentic condition. The chapter shows how Cuvier used these three cultures to justify his reconstruction of extinct animals and to reduce the ideological tensions generated by this reconstruction.