Surface and subsurface stratigraphy of the Burro Canyon Formation, Dakota Sandstone, and intertongued Mancos Shale of the Chama Basin, New Mexico
— Donald E. Owen, Angelique M. Forgas, Shawn A. Miller, Ryan J. Stelly, and Owen, Donald E., Jr.

The Burro Canyon Formation (Lower Cretaceous) and the Dakota Sandstone (Upper Cretaceous: Cenomanian), including two tongues of the Mancos Shale, are present throughout the Chama Basin. The Dakota-Mancos section is divided into 7 marine members in the Chama Basin. The entire stratigraphic section thins southward across the Chama Basin, most notably the Clay Mesa Shale Tongue of the Mancos and the Paguate Sandstone of the Dakota. Prominent sequence-bounding unconformities, K1 and K2, bound the Burro Canyon Formation. A correlative conformity equivalent to the K3 sequencebounding unconformity occurs at the base of the Cubero Sandstone Tongue of the Dakota. A possible sequence boundary occurs at the base of the marine La Jollas bed, a local sandstone lens at the stratigraphic position of the upper Twowells Sandstone Tongue of the Dakota in the southern Chama Basin.