| DOt: Three Forks Formation, Jefferson Formation, and Bighorn Dolomite |
|
| Dd: Darby Formation |
| Je: Ellis Group |
| Jm: Morrison Formation |
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| Js: Sundance and Gypsum Spring Formations |
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| KJm: Cloverly and Morrison(?) Formations |
| Kb: Bacon Ridge Sandstone |
| Kc: Cody Shale |
| Kf: Frontier Formation |
| Kh: Harebell Formation |
| Kl: Landslide Creek Formation, Everts Formation, Eagle Sandstone, Telegraph Creek Formation, Cody Shale, and Frontier Sandstone |
| Kmk: Mowry Shale, Thermopolis Shale, and Kootenai Formation |
|
| Kmt: Mowry and Thermopolis Shales |
| Mm: Madison Group |
| OW: water |
| OWCb: Bighorn(?) Dolomite, Gallatin Limestone, and Gros Ventre Formation |
| Pp: Phosphoria Formation and related rocks |
|
| Ps: Shedhorn Sandstone |
| QTh: Heart Lake Conglomerate |
| Qci: cemented ice-contact deposits localized by hot springs |
| Qf: Falls River Basalt |
| Qge: Plateau Rhyolite - Upper Basin Member - Gerrit Basalt |
| Qh: hot-spring deposits |
| Qhe: hydrothermal-explosion deposits |
| Qiw: Island Park Rhyolite - Warm River Butte dome |
| Qjb: Junction Butte Basalt |
| Qlc: Lewis Canyon Rhyolite |
| Qmj: Mount Jackson Rhyolite |
|
| Qml: Basalt of Mariposa Lake |
| Qmr: Madison River Basalt |
| Qo: Osprey Basalt |
| Qpca: Plateau Rhyolite - Central Plateau Member - Aster Creek flow |
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| Qpcb: Plateau Rhyolite - Central Plateau Member - Buffalo Lake flow |
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| Qpcc: Plateau Rhyolite - Central Plateau Member - Spring Creek flow |
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| Qpcd: Plateau Rhyolite - Central Plateau Member - Dry Creek flow |
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| Qpce: Plateau Rhyolite - Central Plateau Member - Elephant Back flow |
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| Qpcf: Plateau Rhyolite - Central Plateau Member - Solfatara Plateau flow |
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| Qpcg: Plateau Rhyolite - Central Plateau Member - Grants Pass flow |
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| Qpch: Plateau Rhyolite - Central Plateau Member - Hayden Valley flow |
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| Qpci: Plateau Rhyolite - Central Plateau Member - Gibbon River flow |
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| Qpck: Plateau Rhyolite - Central Plateau Member - Douglas Knob flow |
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| Qpcl: Plateau Rhyolite - Central Plateau Member - Summit Lake flow |
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| Qpcm: Plateau Rhyolite - Central Plateau Member - Mary Lake flow |
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| Qpcn: Plateau Rhyolite - Central Plateau Member - Nez Perce Creek flow |
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| Qpcp: Plateau Rhyolite - Central Plateau Member - Pitchstone Plateau flow |
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| Qpcr: Plateau Rhyolite - Central Plateau Member - Bechler River flow |
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| Qpct: Plateau Rhyolite - Central Plateau Member - Trishman Knob flow |
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| Qpcw: Plateau Rhyolite - Central Plateau Member - West Thumb flow |
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| Qpcy: Plateau Rhyolite - Central Plateau Member - West Yellowstone flow |
| Qpm: Plateau Rhyolite - Mallard Lake Member |
| Qpo: Plateau Rhyolite - Obsidian Creek Member, rhyolite flows and domes |
|
| Qpom: Plateau Rhyolite - Obsidian Creek Member, rhyolite-basalt mixed lavas |
| Qpr: Plateau Rhyolite - Roaring Mountain Member |
| Qps: Plateau Rhyolite - Shoshone Lake Tuff Member |
|
| Qpu: Plateau Rhyolite - Upper Basin Member |
| Qs: detrital deposits |
|
| Qsl: Swan Lake Flat Basalt |
| Qso: sediments interlayered with Central Plateau and Upper Basin Members of Plateau Rhyolite |
| Qtn: sediments and basalts of The Narrows |
| Quf: Undine Falls Basalt |
| Qw: basalt of Warm River |
| Qyha: Huckleberry Ridge Tuff of Yellowstone Group - Member A |
|
| Qyhb: Huckleberry Ridge Tuff of Yellowstone Group - Member B |
|
| Qyhc: Huckleberry Ridge Tuff of Yellowstone Group - Member C |
| Qyla: Lava Creek Tuff of Yellowstone Group - Member A |
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| Qylb: Lava Creek Tuff of Yellowstone Group - Member B |
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| Qym: Island Park Rhyolite - Mesa Falls Tuff |
| TKp: Pinyon Conglomerate |
|
| TKv: Volcanic rocks |
| Ta: Absaroka Volcanic Supergroup, undivided |
| Tc: Absaroka Volcanic Supergroup - Washburn Group - Cathedral Cliffs Formation |
| Tcc: Conant Creek Tuff |
| Tch: Absaroka Volcanic Supergroup - Sunlight Group - Crescent Hill Basalt |
| Tec: Absaroka Volcanic Supergroup - Washburn Group - Lamar River Formation - Elk Creek Basalt Member |
| Th: Hominy Peak Formation |
| Ti: Absaroka Volcanic Supergroup intrusive rocks - rhyodacite, quartz latite, quartz monzonite, and granodiorite in the Gallatin Range |
|
| Tid: Absaroka Volcanic Supergroup intrusive rocks - dacite |
| Tl: Absaroka Volcanic Supergroup - Thorofare Creek Group - Langford Formation |
| Tlc: Absaroka Volcanic Supergroup - Washburn Group - Sepulcher Formation - Lost Creek Tuff Member |
| Tlf: Absaroka Volcanic Supergroup - Thorofare Creek Group - Langford Formation - andesite lava flows |
|
| Tli: Absaroka Volcanic Supergroup - Thorofare Creek Group - Intrusive rocks of the Two Ocean and Langford Formations |
| Tlp: Absaroka Volcanic Supergroup - Thorofare Creek Group - Langford Formation - Promontory Member |
| Tlr: Absaroka Volcanic Supergroup - Washburn Group - Lamar River Formation |
| Tlrb: Absaroka Volcanic Supergroup - Washburn Group - Lamar River Formation - bodies of intrusive breccia |
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| Tlrf: Absaroka Volcanic Supergroup - Washburn Group - Lamar River Formation - andesite flows |
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| Tlri: Absaroka Volcanic Supergroup - Washburn Group - Lamar River Formation - Sulphur Creek stock and associated dikes |
|
| Tm: Absaroka Volcanic Supergroup - Sunlight Group - Mount Wallace Formation |
| Tms: Absaroka Volcanic Supergroup - Sunlight Group - Mount Wallace Formation - Slough Creek Tuff Member |
| To: Absaroka Volcanic Supergroup - Thorofare Creek Group - Two Ocean Formation |
| Ts: Absaroka Volcanic Supergroup - Washburn Group - Sepulcher Formation |
| Tsc: Absaroka Volcanic Supergroup - Washburn Group - Sepulcher Formation - principally nonvolcanic conglomerate, fanglomerate, and breccia facies |
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| Tsd: Absaroka Volcanic Supergroup - Washburn Group - Sepulcher Formation - Daly Creek Member |
| Tsf: Absaroka Volcanic Supergroup - Washburn Group - Sepulcher Formation - Fortress Mountain Member |
| Tt: Absaroka Volcanic Supergroup - Sunlight Group - Trout Peak Trachyandesite |
| Ttp: Absaroka Volcanic Supergroup - Sunlight Group - Trout Peak Trachyandesite - Pacific Creek Tuff Member |
| Tw: Absaroka Volcanic Supergroup - Sunlight Group - Wapiti Formation |
| Twi: Absaroka Volcanic Supergroup - Thorofare Creek Group - Wiggins Formation |
| WCp: Park Shale, Meagher Limestone, Wolsey Shale, and Flathead Sandstone |
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| WCs: Snowy Range Formation and Pilgrim Limestone |
| WPCg: Gneiss and schist |
| WPPMt: Tensleep Sandstone and Amsden Formation |
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| WPPq: Quadrant Sandstone and Amsden Formation |
| WTRc: Chugwater and Dinwoody Formations |
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| WTRt: Thaynes(?), Woodside, and Dinwoody Formations |
