OBJECTID|DescriptionOfMapUnits_ID|Category|Type|Symbol|Label|MapUnit|Name|FullName|Age|AgeType|AgeOldest|AgeYoungest|Description|HierarchyKey|ParagraphStyle|AreaFillRGB|AreaFillPatternDescription|GeoMaterialDictID|GeoMaterial|GeoMaterialConfidence|Notes|DataSourceMethod|DescriptionSourceID|created_user|created_date|last_edited_user|last_edited_date|GlobalID
|1|{EBE272EB-7367-4A3F-82C9-5BD30C46ED57}|map unit|map unit, generic|5770|af|af|artificial fill|Artificial fill|Anthropocene|unprovided|Anthropocene|Anthropocene|Fill material used in Nevada Reservoir Dam|02|dmu, map unit|128,077,077||{5B6BE598-6C3E-40CD-9082-7EF21AD7BF1D}|"Made" or human-engineered land|high||997|DAS01|||KMCDONALD|2022-05-23 15:18:00|{EBE272EB-7367-4A3F-82C9-5BD30C46ED57}
2|{DDD89DBA-1D94-429D-BEBE-F5B72B911B2E}|map unit|map unit, generic|1670|Kgd|Kgd|granodiorite|Granodiorite|Late Cretaceous|unprovided|Late Cretaceous|Late Cretaceous|Medium to dark gray, equigranular to porphyritic granodiorite composed of plagioclase, potassium feldspar, quartz, biotite, and hornblende; forms main body of the Ogden Mountain Stock and associated smaller intrusions. Schmidt and others (1994) report K-Ar ages of 81.1 ± 2.8 Ma (biotite) and 85.4 ± 3.9 Ma (hornblende) for the stock.|22|dmu, map unit|222,102,077||{CF5DFA93-4BF2-4B8D-9C5F-FE5ADE0A11B0}|Coarse-grained, intermediate-composition intrusive igneous rock|high||997|DAS01 | DAS02|||KMCDONALD|2022-05-23 15:17:53|{DDD89DBA-1D94-429D-BEBE-F5B72B911B2E}
3|{7ADC2F95-CC14-4ADF-A392-1396B4E15657}|map unit|map unit, generic|5770|pl|pl|placer workings|Placer workings|Anthropocene|unprovided|Anthropocene|Anthropocene|Areas disturbed by historical placer gold operations.|03|dmu, map unit|128,077,077||{EB353141-B5AE-4925-9AAE-1D31020450F8}|Rock and sediment|high||997|DAS01|||KMCDONALD|2022-05-23 15:18:09|{7ADC2F95-CC14-4ADF-A392-1396B4E15657}
4|{D3E3958E-0EE9-4739-8D19-58062D89D942}|map unit|map unit, generic|A140|Qac|Qac|alluvium and colluvium|Alluvium and colluvium|Quaternary: Holocene|unprovided|Holocene|Holocene|Silt, sand, granules, and pebbles deposited on slopes by sheetwash intermixed with locally derived fine-grained colluvium. Thickness generally less than 8 m (20 ft).|07|dmu, map unit|235,222,153||{F0646F40-5324-404D-B3CA-EA0C8C1E65BB}|Colluvium and other widespread mass-movement sediment|medium||997|DAS01|||KMCDONALD|2022-05-23 15:18:58|{D3E3958E-0EE9-4739-8D19-58062D89D942}
5|{32F961B9-C752-4A3A-9107-7A9C7731B01C}|map unit|map unit, generic|0150|Qaf|Qaf|alluvial fan deposit|Alluvial fan deposit|Quaternary: Holocene|unprovided|Holocene|Holocene|Gravel, sand, silt, and clay in deposits with fan-shaped morphology along Nevada Creek and Buffalo Creeks. Large, locally derived clasts are both matrix- and clast-supported. Cobbles are the dominant clast size, but also includes boulders and pebbles. Thickness generally less than 15 m (50 ft).|06|dmu, map unit|255,222,128||{EFF14953-918D-4560-87E8-CB91351003C9}|Alluvial sediment, mostly coarse-grained|high||997|DAS01|||KMCDONALD|2022-05-23 15:19:29|{32F961B9-C752-4A3A-9107-7A9C7731B01C}
6|{551426D5-0370-49FF-83E8-3DB4A71169BD}|map unit|map unit, generic|0010|Qal|Qal|alluvium|Alluvium|Quaternary: Holocene|unprovided|Holocene|Holocene|Gravel, sand, silt, and clay along Nevada Creek and its tributaries. Clasts are generally rounded to subrounded, cobble size and smaller, but boulders also present. Thickness generally less than 10 m (33 ft).|04|dmu, map unit|255,255,222||{EFF14953-918D-4560-87E8-CB91351003C9}|Alluvial sediment, mostly coarse-grained|medium||997|DAS01|||KMCDONALD|2022-05-23 15:21:25|{551426D5-0370-49FF-83E8-3DB4A71169BD}
7|{20B22D39-5028-4989-AE4C-D0141D0069AC}|map unit|map unit, generic|AA30|Qalo|Qalo|alluvium, older than Qal|Alluvium, older than Qal|Quaternary: Pleistocene|unprovided|Pleistocene|Pleistocene|Sand and gravel deposits along Nevada Creek at altitudes 3–35 m above recent stream channel. Clasts generally rounded to subrounded, cobble size and smaller, but boulders also present. Thickness as much as 15 m (50 ft).|11|dmu, map unit|235,235,179||{EFF14953-918D-4560-87E8-CB91351003C9}|Alluvial sediment, mostly coarse-grained|medium||997|DAS01|||KMCDONALD|2022-05-23 15:21:17|{20B22D39-5028-4989-AE4C-D0141D0069AC}
8|{AB31BB03-EDBE-4FD6-941E-A498F2C1A9F0}|map unit|map unit, generic|0160|Qdf|Qdf|debris-flow deposit|Debris-flow deposit|Quaternary: Pleistocene or Holocene|unprovided|Pleistocene|Holocene|Sandy, matrix-supported deposits of local, upslope-derived volcanic rock and sparse sedimentary rock. Clasts range from granule to boulder size. Thickness generally less than 20 m (75 ft).|10|dmu, map unit|255,222,102||{743EA93E-C344-4316-A975-A09F39CC0243}|Debris flows, landslides, and other localized mass-movement sediment|high||997|DAS01|||KMCDONALD|2022-05-23 15:21:11|{AB31BB03-EDBE-4FD6-941E-A498F2C1A9F0}
9|{5D90BB3B-951B-41C9-B13D-D017F4340146}|map unit|map unit, generic|A150|Qls|Qls|landslide deposit|Landslide deposit|Quaternary: Holocene or Pleistocene|unprovided|Pleistocene|Holocene|Mass-wasting deposits of rotated or chaotic beds. The bentonitic Climbing Arrow Member of the Renova Formation (Trca) and units that immediately overlie it are particularly prone to developing landslide deposits. Thickness generally less than 60 m (200 ft).|09|dmu, map unit|235,222,128||{743EA93E-C344-4316-A975-A09F39CC0243}|Debris flows, landslides, and other localized mass-movement sediment|high||997|DAS01|||KMCDONALD|2022-05-23 15:21:48.000001|{5D90BB3B-951B-41C9-B13D-D017F4340146}
10|{22BD13EC-1BB0-4755-96AA-A5735292306C}|map unit|map unit, generic|A170|Qlso|Qlso|landslide deposit, older than Qls|Landslide deposit, older than Qls|Pleistocene|unprovided|Pleistocene|Pleistocene|Mass-wasting deposit of rotated or chaotic beds that slid downslope. Geomorphic expression suggests that deposits are older than Qls. Thickness not known.|12|dmu, map unit|235,222,077||{743EA93E-C344-4316-A975-A09F39CC0243}|Debris flows, landslides, and other localized mass-movement sediment|high||997|DAS01|||KMCDONALD|2022-05-23 15:21:55|{22BD13EC-1BB0-4755-96AA-A5735292306C}
11|{574B86EB-1A24-4315-973E-C4DF453BC2CF}|map unit|map unit, generic|1270|Qm|Qm|mantle deposit|Mantle deposit|Quaternary: Holocene and Pleistocene|unprovided|Pleistocene|Holocene|Unconsolidated deposits on pediments that include sheetwash alluvium, fine-grained colluvium, coarse-grained (pebble, cobble, small boulder) lag from older debris-flow deposits, and regolith. Thickness generally less than 6 m (20 ft).|08|dmu, map unit|222,204,077||{83CA80A1-3518-472D-854F-DAAB121EE141}|Clastic sedimentary rock|low||997|DAS01|||KMCDONALD|2022-05-23 15:23:37|{574B86EB-1A24-4315-973E-C4DF453BC2CF}
12|{379D5D02-6326-4A8F-A0D0-FA635A8AA8B6}|map unit|map unit, generic|AA40|Qpa|Qpa|paludal deposit|Paludal deposit|Quaternary: Holocene|unprovided|Holocene|Holocene|Argillaceous silt, sand, and organic matter deposited in pond or marsh environments. Thickness probably less than 5 m (15 ft).|05|dmu, map unit|235,235,153||{A1ED715F-DCE2-4D18-8AC4-ADFC33E82679}|Peat and muck|high||997|DAS01|||KMCDONALD|2022-05-23 15:23:00|{379D5D02-6326-4A8F-A0D0-FA635A8AA8B6}
13|{16C208CE-8688-4DB0-943E-4E7536F07269}|map unit|map unit, generic|00X0|QTdf|QTdf|debris-flow, older than Qdf|Debris-flow, older than Qdf|Quaternary: Pleistocene, or Tertiary: Pliocene?|unprovided|Pliocene|Pleistocene|Matrix-supported deposits with clasts of upslope-derived volcanic rock and sparse sedimentary rock. Clasts range from granules to boulders. Geomorphic expression suggests the deposits are older than Qdf. Thickness less than 30 m (100 ft).|13|dmu, map unit|255,255,000||{743EA93E-C344-4316-A975-A09F39CC0243}|Debris flows, landslides, and other localized mass-movement sediment|high||997|DAS01|||KMCDONALD|2022-05-23 15:26:01.000001|{16C208CE-8688-4DB0-943E-4E7536F07269}
14|{8427C77F-3636-4485-A44D-9FCAAA2B7FE2}|map unit|map unit, generic|3430|Tba|Tba|basalt|Basalt|Tertiary: Oligocene|unprovided|Oligocene|Oligocene|Black, fine-grained, massive trachybasalt lava flows with sparse olivine and pyroxene phenocrysts. Locally vesicular and weathers to light brown, angular to sub-rounded blocks. A sample from this unit (sec. 12, T. 12 N., R. 10 W.) yielded a K-Ar (whole rock) age of 32.3 ± 1.3 Ma (Mitchell Reynolds, written commun., 2014). Perhaps age-equivalent to basaltic–andesite flows that occur in the Gravely Mountain quadrangle to the south, which yielded a U-Pb zircon age of 30.00 ± 0.19 Ma (Mosolf, 2015).|18|dmu, map unit|179,153,179||{0EB35B4C-25D4-4CC4-B3F4-84063C5D7F3B}|Mafic-composition lava flows|high||997|DAS01 | DAS03|||KMCDONALD|2022-05-23 15:10:29|{8427C77F-3636-4485-A44D-9FCAAA2B7FE2}
15|{22B3D5EA-DF60-43EA-8458-D5A713401CB9}|map unit|map unit, generic|A3X0|Tbgr|Tbgr|boulder gravel|Boulder gravel|Tertiary|unprovided|Tertiary|Tertiary|Dominantly matrix-supported, but locally clast-supported deposits with pebbles to large boulders in clay/silt/sand matrix. Clast composition dominantly Belt Supergroup quartzite with subordinate volcanic and plutonic rock. Matrix in many places has incorporated sediment of the Climbing Arrow Member of Renova Formation (Trca). Deposits have been interpreted as Miocene (Loen, 1990; Schmidt and others, 1994). Contains placer gold (Loen, 1990). May be as thick as 300 m (985 ft).|14|dmu, map unit|235,179,000||{EFF14953-918D-4560-87E8-CB91351003C9}|Alluvial sediment, mostly coarse-grained|medium||997|DAS01 | DAS02 | DAS06|||KMCDONALD|2022-05-23 15:16:05|{22B3D5EA-DF60-43EA-8458-D5A713401CB9}
16|{E87B1EE4-2D8C-493F-B672-6C7B5E27C111}|map unit|map unit, generic|1360|Tbr|Tbr|breccia|Breccia|Tertiary|unprovided|Tertiary|Tertiary|Sedimentary breccia consisting of angular cobble to boulder, medium- to coarse-grained quartzite clasts derived from the Mesoproterozoic Bonner or Mount Shields Formations. Breccia is lithified and has clay infilling. Exposed on bench immediately north of Nevada Lake Reservoir. May have formed as a fault-controlled colluvial wedge along nearby faults. Thickness probably less than 50 m (165 ft).|15|dmu, map unit|222,179,102||{83CA80A1-3518-472D-854F-DAAB121EE141}|Clastic sedimentary rock|low||997|DAS01|||KMCDONALD|2022-05-23 15:27:30|{E87B1EE4-2D8C-493F-B672-6C7B5E27C111}
17|{F85E87ED-834E-445C-AC1B-45CFF69A734E}|map unit|map unit, generic|A310|Tda|Tda|dacite|Dacite|Tertiary: Eocene|unprovided|Eocene|Eocene|Gray and dark gray weathered, aphanitic to slightly porphyritic dacite, trachydacite, and minor trachyandesite lava flows with autobrecciated flow bottoms that are overlain by massive, coherent flow interiors; zones of vesiculation are rarely preserved. Lava flows commonly exhibit distinctive flow banding and form flaggy, angular talus, often with red iron staining on parting surfaces. Aphanitic lavas exhibit a strong trachytic texture consisting mainly of plagioclase microlites, but also include pyroxene, magnetite, and volcanic glass. Slightly porphyritic flows exhibit a similar trachytic texture and groundmass mineralogy but contain subhedral to euhedral phenocrysts of plagioclase, hornblende, and some biotite. Good exposure of the unit occurs in the southwest part of the map area where it overlies the dominantly porphyritic lavas (Tdap) and Phanerozoic through Proterozoic units.|19|dmu, map unit|235,179,222||{9794E6AC-988C-43F5-B3E7-AF45990C41ED}|Intermediate-composition lava flows|high||997|DAS01|||KMCDONALD|2022-05-23 15:27:56|{F85E87ED-834E-445C-AC1B-45CFF69A734E}
18|{0E1952CC-1537-4305-B62E-F76AF2925AF4}|map unit|map unit, generic|3540|Tdap|Tdap|porphyritic dacite|Dacite, porphyritic|Tertiary: Eocene|unprovided|Eocene|Eocene|Gray, green, and red weathered dacite to trachydacite with a coarse, porphyritic texture. Lava flows contain subhedral to euhedral phenocrysts of plagioclase (up to ~5 mm) and minor amphibole, biotite, and quartz. The aphanitic groundmass commonly has a trachytic texture of aligned microlights of plagioclase, with minor amphibole, biotite, and magnetite. Carapaces of autobreccia several meters thick commonly encompass coherent interiors of individual lava flows. This unit typically weathers to blocks or plates, with some outcrops forming hoodoos and spires. U-Pb zircon ages from 3 samples yielded ages of 46.16 ± 0.26 Ma (sec. 31, T. 12 N., R. 9 W.), 46.41 ± 0.18 Ma (sec. 27, T. 12 N., R. 10 W.), and 47.06 ± 0.12 Ma (sec. 8, T. 12 N., R. 9 W.).|21|dmu, map unit|179,128,153||{9794E6AC-988C-43F5-B3E7-AF45990C41ED}|Intermediate-composition lava flows|high||997|DAS01|||KMCDONALD|2022-05-23 14:46:45|{0E1952CC-1537-4305-B62E-F76AF2925AF4}
19|{D6FD8878-41F3-4C1E-BCEA-BFF2FF6799DD}|map unit|map unit, generic|4630|Tdat|Tdat|dacite tuff|Dacite tuff|Tertiary: Eocene|unprovided|Eocene|Eocene|Variably silicified dacite tuff that is massive or flow banded and contains phenocrysts of plagioclase, quartz, biotite, and amphibole. The groundmass consists almost entirely of devitrified glass with some magnetite. Scoriaceous pumice lapilli occur locally and account for up to ~50 percent of the rock. Fine-grained intervals often contain preserved plant and wood fragments. Poorly exposed and distinguished by flaggy chips of white, yellow, and orange weathered float. A U-Pb zircon age from the dacite tuff in the Gravely Mountain quadrangle to the south yielded a date of 47.4 ± 0.19 Ma (Mosolf, 2015), and therefore is considered to be correlative to tuffaceous intervals of map unit Tdap.|20|dmu, map unit|153,102,179||{08616B3E-C261-45C7-B024-A21116834D78}|Intermediate-composition pyroclastic flows|high||997|DAS01 | DAS03|||KMCDONALD|2022-05-23 15:13:04|{D6FD8878-41F3-4C1E-BCEA-BFF2FF6799DD}
20|{2BA27C21-B1A7-43E6-8B7F-61372F705BA7}|map unit|map unit, generic|A2X0|Trca|Trca|Renova Formation, Climbing Arrow Member|Climbing Arrow Member of Renova Formation of Bozeman Group|Tertiary: Eocene|unprovided|Eocene|Eocene|Pale olive, light olive gray, moderate olive brown, and medium light gray bentonitic mudstone, yellowish gray siltstone, and subordinate brownish gray sandstone and gravel/conglomerate lenses. Sandstone dominantly medium- to coarse-grained, with quartz, feldspar, biotite, and rhyolite grains. Gravel/conglomerate consists of clast-supported lenses of rounded granules, pebbles, and cobbles of rhyolite porphyry and other dominantly volcanic lithologies in a sandy, or sand and granule matrix. Bentonitic mudstone typically displays “popcorn” weathering, large desiccation cracks, and is prone to landslide development. Thickness not determined.|17|dmu, map unit|235,204,000||{BA4AC2E3-4497-4C92-B603-75B4A05BC069}|Mostly mudstone|high||997|DAS01|||KMCDONALD|2022-06-06 16:29:20|{2BA27C21-B1A7-43E6-8B7F-61372F705BA7}
21|{F739CDEC-FABB-46A8-AB4E-A3B18ED857F9}|map unit|map unit, generic|0270|Trcp|Trcp|Renova Formation, Cabbage Patch member, informal|Cabbage Patch member, informal, of Renova Formation of Bozeman Group|Tertiary: Miocene and Oligocene|unprovided|Eocene|Eocene|Deposits of limited extent consisting of locally brecciated, fine-grained, grayish orange sandstone or siltstone and remnants of light gray, gastropod-bearing, thin-bedded limestone. Unit is likely the same as in-place deposits on Antelope Hill, located southwest of the map area on the Gravely Mountain quadrangle (Mosolf, 2015). Exposed thickness probably less than 20 m (65 ft) in map area.|16|dmu, map unit|255,204,077||{E6582AD1-79FA-4488-A0F6-E9FB6EBA3291}|Mostly sandstone|medium||997|DAS01 | DAS03|||KMCDONALD|2022-06-06 16:29:34|{F739CDEC-FABB-46A8-AB4E-A3B18ED857F9}
22|{32DEBDEA-0620-45E3-AE1C-78432535153F}|map unit|map unit, generic|5300|w|w|water|Water|Anthropocene|unprovided|Anthropocene|Anthropocene|Nevada Lake Reservoir|01|dmu, map unit|128,179,255||{090E41F1-2A69-4FA6-874B-BBB26CB411B5}|Water or ice|high||997|DAS01|||KMCDONALD|2022-05-23 15:29:31|{32DEBDEA-0620-45E3-AE1C-78432535153F}
23|{69114ABB-E34B-4101-A425-9A87711C50C1}|map unit|map unit, generic|2350|Ybo|Ybo|Bonner Formation|Bonner Formation of Missoula Group of Belt Supergroup|Mesoproterozoic|unprovided|Mesoproterozoic|Mesoproterozoic|Pink to red, medium- to coarse-grained, poorly sorted, feldspathic quartzite. Abundant trough and planar crossbedding in beds typically 0.5–1.0 m thick. Quartzite beds often separated by thin (0.1–1.0 cm), red to maroon argillite beds. Contains sparse subangular granules and small pebbles. Five slabbed and stained samples from the nearby Ophir Creek quadrangle (Lonn and Vuke, 2015) contained 50–75 percent quartz, 15–35 percent potassium feldspar, and 5–15 percent plagioclase. Thickness about 550 m (1,800 ft).|24|dmu, map unit|204,179,128||{58AA9A01-133F-46B5-A023-A044212E1BD3}|Sandstone|high||997|DAS01 | DAS04|||KMCDONALD|2022-05-23 15:09:46|{69114ABB-E34B-4101-A425-9A87711C50C1}
24|{09C2EACB-82FA-47F5-80C8-EB7BC578572F}|map unit|map unit, generic|34X0|Ym|Ym|McNamara Formation|McNamara Formation of Missoula Group of Belt Supergroup|Mesoproterozoic|unprovided|Mesoproterozoic|Mesoproterozoic|Couplets and microcouplets of variegated red and green fine-grained quartzite, siltite, and waxy argillite. Contains diagnostic red or green chert beds and chert rip-up clasts. Mudcracks and mud rip-up clasts are common. Top part is light gray, thick-bedded, fine- to medium-grained crossbedded quartzite with abundant red mud rip-up clasts, uncommon red chert rip-up clasts, and abundant thin, red, mudcracked argillite interbeds. Exposed thickness about 300 m (1,000 ft) thick.|23|dmu, map unit|179,153,000||{E6582AD1-79FA-4488-A0F6-E9FB6EBA3291}|Mostly sandstone|medium||997|DAS01|||KMCDONALD|2022-05-23 15:29:53|{09C2EACB-82FA-47F5-80C8-EB7BC578572F}
25|{36DBF9BB-EF10-406A-B07B-AAADDA2CD36F}|map unit|map unit, generic|5570|Yms2|Yms2|Mount Shields Formation, member 2|Mount Shields Formation, member 2, informal, of Missoula Group of Belt Supergroup|Mesoproterozoic|unprovided|Mesoproterozoic|Mesoproterozoic|Pink to red, poorly sorted, medium- to coarse-grained, feldspathic quartzite. Abundant planar and trough crossbeds. Contains sparse subangular granules. Lower part is thinner bedded, consisting of couples of white to pink, medium-grained quartzite and thin red argillite. Bases of quartzite beds contain abundant red mud chips. The lower part of the unit was included in the top part of the Mount Shields Formation, member 1 by Schmidt and others (1994). Two slabbed and stained samples from the Ophir Creek 7.5' quadrangle (Lonn and Vuke, 2015) east of the Avon Valley contained 65–75 percent quartz, 5–15 percent potassium feldspar, and 20 percent plagioclase. Difficult to distinguish from the Bonner Formation (unit Ybo). Thickness about 520 m (1,700 ft).|26|dmu, map unit|128,128,077||{58AA9A01-133F-46B5-A023-A044212E1BD3}|Sandstone|high||997|DAS01 | DAS02 | DAS04|||KMCDONALD|2022-06-06 16:30:46|{36DBF9BB-EF10-406A-B07B-AAADDA2CD36F}
26|{5DDF1BD0-ACCF-4C1F-B1B7-08D1054C7EE9}|map unit|map unit, generic|3350|Yms3|Yms3|Mount Shields Formation, member 3|Mount Shields Formation, member 3, informal, of Missoula Group of Belt Supergroup|Mesoproterozoic|unprovided|Mesoproterozoic|Mesoproterozoic|Grayish red to blackish red, fine-grained quartzite to argillite couples and couplets with abundant desiccation cracks, mudchips, and diagnostic cubic salt casts. Includes green interbeds and some red microlaminae. Thickness about 275 m (900 ft).|25|dmu, map unit|179,179,128||{33F67A5B-8B6D-493B-BD7F-A3241BF3BB13}|Sandstone and mudstone|high||997|DAS01|||KMCDONALD|2022-06-06 16:29:41|{5DDF1BD0-ACCF-4C1F-B1B7-08D1054C7EE9}
27|{8634B2D5-E2E7-443B-890E-1B7460F52649}|map unit|map unit, generic|5670|Ypg|Ypg|Piegan Group|Piegan Group of Belt Supergroup|Mesoproterozoic|unprovided|Mesoproterozoic|Mesoproterozoic|Tan and dark gray dolomite, dark gray limestone, dark gray to tan argillite, siltite, calcareous siltite, and fine-grained quartzite; weathers grayish orange to yellowish gray. The upper 300 m (985 ft) consists of dark gray limestone interbedded with dark gray calcareous argillite that is interpreted as the Wallace Formation, the upper part of the Piegan Group. Below this interval, the Helena Formation is characterized by cycles consisting of a basal clastic zone of tan to gray siltite and fine-grained quartzite that is overlain by tan dolomite, and capped by dark gray argillaceous or stromatolitic limestone. Oolite beds are commonly associated with the stromatolites. Crinkly molar-tooth structure, syneresis cracks, fluid-escape structures, and recessive weathering calcitic pods are common sedimentary structures. Adjacent to the Ogden Mountain Stock, the unit is contact metamorphosed to light and dark green hornfels with diopside and/or tremolite. Base not exposed, but at least 1,220 m (4,000 ft) thick.|29|dmu, map unit|128,102,077||{50C3A3D5-8DE1-4D41-BC42-99D99E44EF39}|Mostly carbonate rock|high||997|DAS01|||KMCDONALD|2022-05-23 15:30:45|{8634B2D5-E2E7-443B-890E-1B7460F52649}
28|{891AEB5C-84D7-4F10-8EF7-63923EC0846B}|map unit|map unit, generic|3330|Ysh|Ysh|Shepard Formation|Shepard Formation of Missoula Group of Belt Supergroup|Mesoproterozoic|unprovided|Mesoproterozoic|Mesoproterozoic|Dolomitic and non-dolomitic, dark green siltite and light green argillite in microlaminae. Couplets of non-dolomitic red quartzite to argillite. Poorly exposed, but weathers to thin plates that, when dolomitic, have a characteristic orange-brown weathering rind. Ripples and load casts are common; mudcracks are rare. The upper half of the formation contains intervals of pink to gray, fine-grained feldspathic quartzite included in Mount Shields Formation, member 1 by Schmidt and others (1994). However, we place the formation’s upper contact at the top of a 50-m (160-ft) thick interval of distinctive rose-colored, dolomitic siltite–argillite couplets as was done in areas to the west (Lonn and others, 2010). The lower contact is placed at the bottom of the lowest dolomite-bearing intervals. A stromatolite bed is often found near the base. Thickness about 610 m (2,000 ft).|27|dmu, map unit|179,179,179||{50C3A3D5-8DE1-4D41-BC42-99D99E44EF39}|Mostly carbonate rock|high||997|DAS01 | DAS02 | DAS05|||KMCDONALD|2022-05-23 15:15:52|{891AEB5C-84D7-4F10-8EF7-63923EC0846B}
29|{FFE8DE72-E5D6-4AB8-B224-E3B29CBA1E91}|map unit|map unit, generic|4560|Ysn|Ysn|Snowslip Formation|Snowslip Formation of Missoula Group of Belt Supergroup|Mesoproterozoic|unprovided|Mesoproterozoic|Mesoproterozoic|Interbedded intervals of quartzite to grayish-red argillite couplets, dark green siltite to light green argillite couplets, and microlaminated couplets. Desiccation cracks and mud rip-up clasts are common throughout. Argillite beds often contain irregular “bumps” thought to be ill-defined salt casts or structures related to microbial mats. Contains beds and lenses of distinctive white, coarse-grained, well-sorted, feldspar-poor quartzite with some well-rounded, frosted (dull, opaque surface) quartz grains. Lower 50 m (160 ft) dominated by microlaminated green dolomitic siltite and argillite. Upper 50–75 m (160–250 ft) is red, flat-laminated medium-grained quartzite in beds 0.5–1.0 m thick. Thickness about 1,430 m (4,700 ft).|28|dmu, map unit|153,128,102||{33F67A5B-8B6D-493B-BD7F-A3241BF3BB13}|Sandstone and mudstone|high||997|DAS01|||KMCDONALD|2022-05-23 15:31:39|{FFE8DE72-E5D6-4AB8-B224-E3B29CBA1E91}
