The Culebra Formation (Tcb) is a geologic formation in Panama. It preserves fossils dating back to the Miocene period; Early Miocene epoch, Aquitanian to Burdigalian stages. Fossils of Culebrasuchus have been found in and named after the formation. The thickness of the formation is at least 250 metres (820 ft) thick, and the age has been estimated as from 23 to 19 Ma.