The Bell Ranch Formation is a Late Jurassic rock unit in eastern and northeastern New Mexico and the western Oklahoma Panhandle, notable for its sedimentary beds and preserved dinosaur tracks. Near Tucumcari, it consists of alternating light gray sandstone and brownish red siltstone, with gypsum nodules in the upper beds, while farther north in the Dry Cimarron valley it shifts to darker mudstone with more abundant gypsum and less thickness. These regional differences reflect changing depositional conditions. Its best-known fossils are trackways of large dinosaurs, including theropod tracks, making it an important Jurassic track-bearing unit of the southern High Plains.