Cretaceous stratigraphy and biostratigraphy, east-central New Mexico
— Spencer G. Lucas, Barry S. Kues, and Adrian P. Hunt

Cretaceous strata exposed in east-central New Mexico belong to the (in ascending order) Tucumcari, Mesa Rica, Pajarito, Romerovine, Graneros and Greenhorn formations. The Mesa Rica, Pajarito and Romeroville formations are the Dakota Group in this region. The Tucumcari Formation is as much as 25 m thick and is mostly marine shale and minor bioturbated sandstone and limestone. The Mesa Rica Sandstone is mostly cross bedded and ripple laminated quartzarenite as much as 43 m thick. The Pajarito Formation is as much as 30 m thick and is mostly silty mudstone and bioturbated quartzarenite. The Romeroville Sandstone is <10 m of bioturbated and cross bedded quartzarenite. The Graneros Shale is as much as 67 m of shale, and the Greenhorn Formation consists of the Lincoln (up to 34 m of shale and calcarenite), Hartland (up to 11 m of shale and bentonite) and Bridge Creek (up to 9 m of limestone and shale) members. We document a specimen of the late Albian ammonite Mortoniceras leonense from the lower Mesa Rica Sandstone. The Tucumcari, Mesa Rica and Pajarito formations are of late Albian age, whereas the Romeroville, Graneros and (most of) the Greenhorn formations are of Cenomanian age. The youngest Cretaceous strata preserved in east-central New Mexico are early Turanian beds of the upper part of the Bridge Creek Member of the Greenhorn Formation.