Lehman (1994) advocated a simplified stratigraphy of up to five geologic formations. The basal unit is the Santa Rosa Sandstone, a braided stream channel-related facies. The Santa Rosa is overlain by the Tecovas Formation, which is dominated by overbank (distal floodplain) deposits with lenses of channel-deposits. Minor lacustrine deposits are also occurring. The Trujillo Sandstone, channel-deposits, and Cooper Canyon Formation, overbank deposits with minor channel and lacustrine deposits, are separated from the Santa Rosa-Tecovas by an unconformity. In eastern New Mexico, the Redonda Formation overlies the Cooper Canyon Formation. The Redonda has gradational eastward transition into the upper Cooper Canyon Formation.