 Fossils of species within this genus have been found in England, France, Denmark, Morocco and Mali.Remains have also been found in North America, including Maryland and Virginia (from the early Eocene Nanjemoy Formation), Georgia and Mississippi.These species varied broadly in size; "Palaeophis casei" is the smallest at 1.3 metres of length, while "Palaeophis colossaeus", known from isolated vertebrae, is the largest at the estimated size limits for the genus at over in length, making it one of the largest known snakes.