San Juan Basin
Coal-bearing, primarily in the Fruitland.
Mudstone, shale, and sandstone; coal-bearing.
San Juan Basin
Mancos Shale, upper part
Divided into Upper and Lower parts by Gallup Sandstone.
Alluvium
Transgressive marine sandstone.
Mancos Shale, lower part
Restricted to Chuska Mountains.
Marine shale and mudstone.
Upper Jurassic nonmarine rocks.
Prominent cliff-forming marine sandstone.
San Juan Basin
Generally regressive marine sandstone.
Landslide deposits on western flanks of Socorro Mountains not shown for clarity.
Regressive marine sandstone in McKinley and Sandoval Counties; the lower, Hosta Tongue, of Point Lookout is transgressive and is separated from main body by the Satan Tongue of Mancos Shale.
Includes Oak Canyon, Cubero, and Paguate Tongues; includes Clay Mesa Tongue of Mancos Shale.
Consists of Entrada Sandstone, Todilto and Summerville Formations, Bluff Sandstone, and locally Zuni Sandstone (or only Acoma Tongue of Zuni).
Includes Cliff House Sandstone, Menefee Formation, and Point Lookout Sandstone.
May locally include Wingate Sandstone.
Volcaniclastic sedimentary rocks of intermediate composition in northern San Juan Basin.
Includes Bearwallow Mountain Andesite and basaltic andesite of Mangas Mountain; also near vent basaltic lavas and shallow intrusions in the Chuska Mountains.
Continental red beds.
Beartooth and Sarten Formations are in part Albian. Includes Virden Formation in northern Hidalgo County, Ringbone Formation in Hidalgo, Luna and Grant Counties, Mancos Shale in Silver City area.
Includes many long basaltic andesite dikes of Oligocene age near Pie Town, Acoma, Riley, Chupadera, Truth or Consequences, Roswell, Raton, and Dulce; and several elongate or shoestring-like sills of basalt or basaltic andesite. Also includes basaltic necks of Pliocene age that dot the landscape northeast of Mount Taylor. Where dikes extend into Quaternary alluvium the contact is an unconformity.
Map unit includes Moenkopi Formation (Middle Triassic) at base in many areas; in eastern part of state the following five formations are mapped: TRr, TRb, TRt, TRg, and TRs.
In southwest includes the basalt-bearing Broken Jug Formation.
Includes monzonitic to granitic plutons, stocks, laccoliths, and porphyritic dikes in deeply eroded magmatic centers; and andesitic, dacitic, or rhyolitic plugs and dikes near cauldrons or stratovolcanoes. In the Latir field, fine-grained rhyolitic dikes commonly cut coarse-grained granitic plutons. Includes alkaline laccoliths, plugs, and dikes in Colfax County. North-trending dikes near Capitan include some mafic diabase dikes.