El Peñón Formation
The formation was defined and named in 1982 by Ulloa after El Peñón, Cundinamarca. The El Peñón Formation has at is type section a thickness of , and is characterised by a sequence of calcareous shales and siltstones. The middle part of the sequence contains gypsum. Fossils of the ammonites "Cheloniceras sp." and "Epicheloniceras sp. aff. carlosacostai" have been found in the El Peñón Formation. The El Peñón Formation, part of the Villeta Group, conformably overlies the Trincheras Formation and is conformably overlain by the Capotes Formation. The age has been estimated to be Late Aptian. Stratigraphically, the formation is time equivalent with the Tablazo Formation and a lateral facies equivalent of the Socotá Formation. The formation has been deposited in a shallow marine platform environment. In the Late Aptian, central Colombia was dominated by shallow marine carbonate platform environments. The El Peñón Formation, restricted to Cundinamarca, is locally found around its type locality, between Bituima and Guayabal de Síquima, and along the road from Villeta to Sasaima. Geology of the Eastern Hills
 Geology of the Ocetá Páramo
 Geology of the Altiplano Cundiboyacense
Description
The formation consists of calcareous shales and siltstones and dates to the Early Cretaceous period; Late Aptian epoch and has a measured thickness at its type section of . Ammonite fossils have been found in the formation, deposited in a shallow marine platform environment.