The Apón Formation is a geological formation in northwestern Venezuela (Maracaibo Basin) and northern Colombia (La Guajira), whose thick-bedded limestone interbedded with subordinate amounts of dark gray calcareous shale and sandy shale strata date back to the Early Cretaceous (Late Aptian epoch). Pterosaur remains of Ornithocheiridae indet. (=?Anhangueridae indet.) are among the fossils that have been recovered from the formation. Fossil content The following fossils, among others, have been found in the Apón Formation at Toas island: Spiroculina sp., Orbitolina concava, Gryphaeostrea, Amphidonte (Ceratostreon) boussingaulti, Ostrea sp., Amphitriscoelus waringi, Requienia sp., Parahoplites sp., Cheloniceras sp., Quinqueloculina sp., Triloculina sp., and Panopea (Myopsis) plicata in Río Negro. See also List of pterosaur-bearing stratigraphic units References Bibliography Geologic formations of Colombia Geologic formations of Venezuela Lower Cretaceous Series of South America Cretaceous Colombia Cretaceous Venezuela Limestone formations Marl formations Shallow marine deposits Aptian Stage Fossiliferous stratigraphic units of South America Paleontology in Venezuela Geography of La Guajira Department Geography of Zulia Maracaibo basin Colombia–Venezuela border