This picture is of a large (greater than 30 cm wide)
Knemiceras uhligi (Choffat) ammonite fossil. It was found at Baforeira, Parde, Cascais, Portugal and dates to the Cretaceous Period (Albian, about 110 million years ago). As of August 2026 on display near front entrance of Academia das Ciências de Lisboa Museu Geológico in Portugal.