The Bajo de la Carpa Formation is a geologic formation of the Neuquén Basin that crops out in northern Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the oldest of two formations belonging to the Río Colorado Subgroup within the Neuquén Group. Formerly, that subgroup was treated as a formation, and the Bajo de la Carpa Formation was known as the Bajo de la Carpa Member.

At its base, this formation conformably overlies the Plottier Formation of the older Río Neuquén Subgroup, and it is in turn overlain by the Anacleto Formation, the youngest and uppermost formation of the Neuquén Group.

The Bajo de la Carpa Formation can reach 150 metres (490 ft) in thickness in some locations, and consists mainly of sandstones of various colors, all of fluvial origin, with thin layers of mudstone and siltstone in between. Geological features such as geodes, chemical nodules, impressions of raindrops, and paleosols (fossil soils) are commonly found in this formation as well.

Reptiles reported from the Bajo de la Carpa Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Lomalatachelys	L. neuquina				A snake-necked turtle
Dinilysia	D. patagonica				A Snake
Paleochelco	P. occultato				A lizard
Podocnemidoidea	Indeterminate.

Small nests with eggs inside, found in this formation, probably belonged to the bird Neuquenornis. Fossil wasp nests have also been found in these rocks.

Crocodylomorphs reported from the Bajo de la Carpa Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Barrosasuchus	B. neuquenianus
Comahuesuchus	C. brachybuccalis
Cynodontosuchus	C. rothi
Lomasuchus	L. palpebrosus.
Gasparinisuchus	G. peirosauroides
Kinesuchus	K. overoi
Neuquensuchus	N. universitas
Notosuchus	N. lepidus
	N. terrestris
Peirosaurus	P. torminni			A fragmentary skull and a partial postcranial skeleton.

Fish reported from the Bajo de la Carpa Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Rinconodus	R. salvadori				A ceratodontid lungfish

Ornithischians reported from the Bajo de la Carpa Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Ankylosauria	Indetermidate.
Mahuidacursor	M. lipanglef				An ornithopod.

Sauropods reported from the Bajo de la Carpa Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Bonitasaura	B. salgadoi			A partial sub-adult skeleton with a lower jaw, a partial vertebrae series, and limb bones.	A titanosaur.
Inawentu	I. oslatus	Rincón de los Sauces.		A partially articulated skeleton, including a nearly complete skull, Several vertebrae from the atlas to the end of the sacrum, and both ilia	A titanosaur.
Overosaurus	O. paradasorum		Upper	A fully articulated vertebral series consists of rib bones, dorsals, and ilium.	A titanosaur.
Rinconsaurus	R. caudamirus	Rincón de los Sauces.	Lower.	The fossil remains included vertebrae, limb bones, scapula, hip bones (pubis, ilium, and ischium) and several ribs.	A titanosaur.
Traukutitan	T. eocaudata	Sitio Trauku.	Lower	A partial semi-articulated skeleton including both thigh bones and thirteen vertebrae from the anterior and middle tail.	A titanosaur.

Theropods reported from the Bajo de la Carpa Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Achillesaurus	A. manazzonei		Upper	A partial skeleton consists of a sacral vertebra, four tail vertebrae, part of the left thighbone, shin, and foot, and the left ilium.	An alvarezsaurid.
Alvarezsaurus	A. calvoi				An alvarezsaurid.
Diuqin	D. lechiguanae	"the isthmus between the southeast coast of Lago Barreales and the northwest coast of Lago Mari Menuco"		A fragmentary but associated partial skeleton	An unenlagiine.
Llukalkan	L. aliocranianus	La Invernada site.		A partial skull.	An abelisaur.
Neuquenornis	N. volans		Upper	A skull and a partial postcranial remains.	A enantiornithine bird.
Patagopteryx	P. eferrariisi		Upper		The oldest known flightless bird.
Tratayenia	T. rosalesi			A well-preserved partial skeleton	A megaraptoran theropod.
Velocisaurus	V. unicus				A noasaur.
Viavenator	V. exxoni				An abelisaur.

• List of fossil sites
• List of dinosaur bearing rock formations
• Mata Amarilla Formation, contemporaneous formation of the Austral Basin

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• Leardi, Juan Martín; Pol, Diego; Brandoni de Gasparini, Zulma (2018). "New Patagonian baurusuchids (Crocodylomorpha; Notosuchia) from the Bajo de la Carpa Formation (Upper Cretaceous; Neuquén, Argentina): New evidences of the early sebecosuchian diversification in Gondwana". Comptes Rendus Palevol. 17 (8): 504–521. Bibcode:2018CRPal..17..504L. doi:10.1016/j.crpv.2018.02.002. hdl:11336/98526. S2CID 134148996. Retrieved 2019-02-21.