The Bogotá Formation (Spanish: Formación Bogotá, E1-2b, Tpb, Pgb) is a geological formation of the Eastern Hills and Bogotá savanna on the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The predominantly shale and siltstone formation, with sandstone beds intercalated, dates to the Paleogene period; Upper Paleocene to Lower Eocene epochs, with an age range of 61.66 to 52.5 Ma, spanning the Paleocene–Eocene Thermal Maximum. The thickness of the Bogotá Formation ranges from 169 metres (554 ft) near Tunja to 1,415 metres (4,642 ft) near Bogotá. Fossils of the ungulate Etayoa bacatensis have been found in the Bogotá Formation, as well as numerous reptiles, unnamed as of 2017.
Paleogeography of Northern South America 50 Ma, by Ron Blakey
Image: Blakey Pleist COL
Image: Blakey 020Ma COL
Image: Blakey 035Ma COL
The Eastern Hills are a chain of hills forming the eastern natural boundary of the Colombian capital Bogotá. They are part of the Altiplano Cundiboyacense, the high plateau of the Eastern Ranges of the Colombian Andes. The Eastern Hills are bordered by the Chingaza National Natural Park to the east, the Bogotá savanna to the west and north, and the Sumapaz Páramo to the south. The north-northeast to south-southwest trending mountain chain is 52 kilometres (32 mi) long and its width varies from 0.4 to 8 kilometres. The highest hilltops rise to 3,600 metres (11,800 ft) over the western flatlands at 2,600 metres (8,500 ft). The Torca River at the border with Chía in the north, the boquerón Chipaque to the south and the valley of the Teusacá River to the east are the hydrographic limits of the Eastern Hills.
View of the Eastern Hills, from Salitre
The Eastern Hills are clearly visible on this photo of Bogotá; the darker green elevated areas bordering the Colombian capital. North is in the upper left of the image.
Aguanoso Hill
An example of the organic shale of the Chipaque Formation