San Gregorio Formation, Venezuela

San Gregorio Formation
Stratigraphic range: Zanclean-Chibanian (Chapadmalalan-Lujanian) ~5.33–0.709100 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Unit of	Urumaco stratigraphic section
Sub-units	Vergel Member Cocuiza Member
Overlies	Codore Formation
Thickness	~570 m (1,870 ft)
Lithology
Primary	Sandstone, mudstone
Other	Limestone
Location
Country	Venezuela
Type section
Named for	San Gregorio, Venezuela

The San Gregorio Formation is a lithostratigraphic unit dating back to the Pliocene to Pleistocene of Venezuela. The formation is split into three members, the older Vergel Member (Late Pliocene to earliest Pleistocene), the Cocuiza Member (Pleistocene) and the Río Seco Member. During this time the region is thought to have been covered by a mixed environment of open grassland and forested areas surrounding a permanent freshwater system. The diverse fauna of the San Gregorio Formation, including a variety of freshwater fish, crocodilians, turtles and snakes, also includes many mammals interpreted to have been part of the first major wave of the Great American Interchange in addition to native clades such as glyptodonts, ground sloths and caviomorph rodents.^[1]