Named as a member (1 of 5) of Chinle Formation for Bluewater Creek, Cibola Co, NM. Type section measured in NE1/4 NW1/4 SE1/4 and W1/2 NE1/4 sec 36, T13N, R12W, Cibola Co, San Juan basin where it is 52.2 m and of dominantly gray-red and red-brown sandstone, silty mudstone, and sandy siltstone. Formerly called "Division D" of Chinle, lower red member of Chinle, and Monitor Butte Member of Chinle. Authors believe Monitor Butte should be restricted to the dominantly green-gray bentonitic claystone and clayey fine-grained sandstone of San Juan Co, UT. A thin carbonaceous shale within member formerly referred to as Ciniza Lake Beds, a name abandoned in this report. Conformably overlies mottled strata and conformably underlies Petrified Forest Member, both of Chinle. History of nomenclature chart. Cross section. A second section measured in E1/2 NW1/4 NE1/4 and N1/2 NE1/4 SW1/4 NE1/4 sec 9, T14N, R16W, McKinley Co, 36.9 ft thick mostly of gray massive noncalcareous to slightly calcareous mudstone with nodular siderite and nodular calcite in layers and two red-brown siltstone layers interbedded. Extensive fossil flora, coelacanth fish scales, coprolites, phytosaurs, METOPOSAURUS, and an aetosaur. Vertebrate fossils suggest Carnian, Late Triassic age.

Source: GNU records (USGS DDS-6; Denver GNULEX).