rock unit,unit name,age,description,fossil,radiometric age,source,class,quadrangle,rock class,nsaclass,label, nsamod,qclass
    "btu","Bedrock unknown","Unknown but likely Precambrian or older","type unknown; relations uncertain","","","OP002","9001","Ophir","","99","pCu","",""
    "bu  pc /TrMc","None","Uncertain","Map shows questionable identification of unit.","","","OP002","902","Ophir","Metamorphic","99","bu","",""
    "Qac","Alluvium","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.  Chiefly silt and very fine sand.  Terrace deposits largely fluival but in part lacustrine; slope deposits primarily eolian and colluvial.   


","The ""Palisades"" along the Yukon have yielded Pleistocene vertebrate fauna including mammoth and bison remains. ","","MZ002","100","Melozitna","Unconsolidated","100","Qal","",""
    "Qu","None","Quaternary","Undifferientiated lowland silt, sand, muck, and gravel","","","OP002","102","Ophir","Unconsolidated","100","Qs","",""
    "Qf","Floodplain deposits","Quaternary","Floodplain deposits","","","KT002","100","Kateel River","Unconsolidated","100","Qs","",""
    "Qac","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","Quaternary","Chiefly silt and very fine sand.  Includes extensive loess deposits","","","MD002","105","Medfra","Unconsolidated","100","Qs","",""
    "Qcal","Colluvium and alluvium, undifferentiated","Quaternary","Silt and sand mantling broad, flat valleys","","","TN002","100","Tanana","Unconsolidated","100","Qs","",""
    "Qu","Alluvium","Quaternary","Silt, sand, and gravel of stream beds, flood plains, and terraces



","","","RB003","100","Ruby","Unconsolidated","100","Qs","",""
    "Q","Surficial materials, undivided","Quaternary","Includes stream alluvium, colluvial deposits, terrace gravel, eolian deposits, and glacial deposits","","","TN003","100","Tanana","Unconsolidated","100","Qs","",""
    "Qc","Fluvial, colluvial, and eolian terrace and slope deposits, undivided","Holocene and Pleistocene","Silt and very fine sand","","","UL002","109","Unalakleet","Unconsolidated","100","","",""
    "Qu","Unconsolidated deposits","Quaternary","Silt, sand, and gravel of stream beds, flood plains, and terraces



","","","RB004","100","Ruby","Unconsolidated","100","Qs","",""
    "Q","Surficial deposits","Quaternary","Alluvium, colluvium, and loess","","","RB002","100","Ruby","Unconsolidated","100","Qs","",""
    "Q","Surficial deposits","Quaternary","Undifferentiated glacial drift, eolian and alluvial deposits","","","BT002","100","Bettles","Unconsolidated","100","Qs","",""
    "Qae","Undifferentiated alluvium, eolian terrace and slope deposits","Pleistocene and Recent","Undifferentiated alluvium and eolian terrace and slope deposits of silt and very fine sand","","","HU002","115","Hughes","Unconsolidated","100","Qs","",""
    "Qae","Undifferentiated alluvial and eolian deposits","Quaternary","Undifferentiated alluvial and eolian deposits, chiefly silt and fine sand.  Includes glacial outwash and fan gravels locally.","","","SH002","11","Shungnak","Unconsolidated","100","Qs","",""
    "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","","","SP003","706","Survey Pass","Unconsolidated","100","","",""
    "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","","","BT003","100","Bettles","Unconsolidated","100","Qs","",""
    "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","","","AR003","703","Ambler River","Unconsolidated","100","Qs","",""
    "Qua","Alluvial, colluvial, glacial, and windblown deposits, undivided","Quaternary","Glacial deposits, alluvuim, colluvium, and landslides.","","","WI003","113","Wiseman","Unconsolidated","100","Qs","",""
    "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","","","WI003","113","Wiseman","Sedimentary","100","","",""
    "Qua","Alluvium","Quaternary","Undifferentiated alluvial, colluvial and eolian terrace and slope deposits","","","RB009","811","Ruby","Unconsolidated","100","Qua","",""
    "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels","","","SE004","400","Selawik","Unconsolidated","100","","","1000"
    "Qc","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels","","","UL003","200","Unalakleet","Unconsolidated","100","","","1000"
    "Q","Surficial deposits","Quaternary","Undifferentiated glacial drift, eolian and alluvial deposits","","","wi004","100","Wiseman","Unconsolidated","100","Qs","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.
","","","OP005","102","Ophir ","Unconsolidated","100","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.

","","","OP005","910","Ophir ","Unconsolidated","100","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.","","","HU003","100","Hughes","Unconsolidated","100","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.","","","MD004","105","Medfra","Unconsolidated","100","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.","","","TN008","30100","Tanana","Unconsolidated","100","","",""
    "Q","Surficial deposits","Quaternary","Alluvium, colluvium, and loess","","","RB005","100","Ruby","Unconsolidated","100","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels","","","NL004","500","Nulato","Unconsolidated","100","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided","Quaternary, Holocene and Pleistocene","Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravel","","","KT004","901","Kateel River","Unconsolidated","100","Qs","",""
    "Qal","Alluvium","Quaternary","Silt, sand, and gravel of stream beds, flood plains, and terraces



","","","RB002","101","Ruby","Unconsolidated","105","Qa","",""
    "Qfy","Younger flood-plain deposits","Quaternary","Light-gray micaceous silt.  Sand and gravel along streams that drain bendrock uplands.  Characterized physiographically by badrs, oxbows, meander scars, abandoned channels, and other evidence of recent flood-plain building.

","","","MZ002","110","Melozitna","Unconsolidated","105","Qac","",""
    "Qal","Alluvium","Quaternary","Silt, sand and gravel of streambeds, flood plains and terraces","","","NL002","101","Nulato","Unconsolidated","105","Qa","",""
    "Qa","None","Quaternary","Alluvium","","","OP002","101","Ophir","Unconsolidated","105","Qal","",""
    "Qfy","Younger flood-plain deposits","Quaternary","Light-gray micaceous silt.  Sand and gravel along streams that drain bedrock uplands","","","KT002","102","Kateel River","Unconsolidated","105","Qac","",""
    "Qal","Recent alluvium","Holocene","Sandy gravel and sandy silt, forms flood plain of modern rivers and streams.","","","TN002","105","Tanana","Unconsolidated","105","Qal","",""
    "Qags","Older alluvium","Quaternary","Coarse, silty sand and fine gravel; generally forms terrace sloping up and away from floodplains of streams and rivers","","","TN002","111","Tanana","Unconsolidated","105","Qa","",""
    "Qfy","Younger flood-plain deposits","Quaternary","Chiefly light-gray micaeous silt along Yukon and Koyukuk rivers.  Silt, sand and gravel along streams that drain bedrock uplands.  Locally include some terrace and fan deposits along narrow tributary valleys.  Mapped from aerial photographs.","","","NL003","100","Nulato","Unconsolidated","105","","",""
    "Qf","Flood-plain deposits","Holocene","Silt, sand, and gravel along floodplains of stream valleys","","","UL002","110","Unalakleet","Unconsolidated","105","","",""
    "Qf","Flood-plain deposits","Quaternary","Flood-plain deposits.  Gravel, sand, and silt along flood-plains of major stream valleys","","","CA002","100","Candle","Unconsolidated","105","Qa","",""
    "Qfp","Flood Plain deposits","Pleistocene and recent","Flood Plain deposits of gravel, sand, and silt along flood plains of major drainages","","","HU002","110","Hughes","Unconsolidated","105","","",""
    "Qfp","Flood-plain deposits","Quaternary","Silt, sand, and gravel along flood plains of major drainages.  Locally includes some fan and terrace deposits along narrow tributary valleys","","","SH002","1","Shungnak","Unconsolidated","105","Qa","",""
    "Qft","Flood-plain deposits","Quaternary","Silt, sand, and gravel along flood plains of major drainages.  Locally includes some fan and terrace deposits along narrow tributary valleys","","","SE002","105","Selawik","Unconsolidated","105","Qa","",""
    "Qa","Alluvial deposits","Quaternary","Unconsolidated gravel, sand, silt, and clay","","","BM002","102","Baird Mountains","Unconsolidated","105","Qa","",""
    "Qf","Floodplain and tidal flats deposits.","Quaternary","Floodplain and tidal flats deposits.  Gravel, sand, silt, and peat","","","SP003","702","Survey Pass","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits","Quaternary","Floodplain and tidal flats deposits.  Gravel, sand, silt, and peat.","","","BT003","109","Bettles","Unconsolidated","105","Qa","",""
    "Qf","Floodplain and tidal flat deposits.","Quaternary","Floodplain and tidal flat deposits.  Gravel, sand, silt, and peat.","","","AR003","701","Ambler River","Unconsolidated","105","Qa","",""

    "Qf","Floodplain and tidal flat deposits.","Quaternary","Floodplain and tidal flat deposits.  Gravel, sand, silt, and peat.","","","BM003","1000","Baird Mountains","Unconsolidated","105","Qa","",""
    "Qf","Floodplain and tidal flats deposits","Quaternary","Floodplain and tidal flats deposits. Gravel, sand, silt, and peat","","","WI003","110","Wiseman","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits","Quaternary","Floodplain and tidal flats deposits","","","RB009","810","Ruby","Unconsolidated","105","Qf","",""
    "Qf","Flood Plain deposits","Pleistocene and recent","Flood Plain deposits of gravel, sand, and silt along flood plains of major drainages","","","HU003","217","Hughes","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.

","","","OP005","101","Ophir","Unconsolidated","105","","",""
    "Qf ","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","KT004","902","Kateel River ","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","MD004","700","Medfra","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","MZ004","730","Melozitna","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","TN008","30105","Tanana","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","KT004","4102","Kateel River ","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","KT004","300","Kateel River ","Unconsolidated","105","","",""
    "Qf","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt","","","NL004","105","Nulato","Unconsolidated","105","","",""
    "Qaf","Alluvial fan deposits","Quaternary","Gravel, silt, and sand, commonly occur at mouth of small side canyons.  Includes some colluvial deposits.","","","TN002","106","Tanana","Unconsolidated","106","Qaf","",""
    "Qc","None","Quaternary","Colluvium","","","OP002","104","Ophir","Unconsolidated","107","Qc","",""
    "Qc","Colluvium, undifferentiated","Quaternary","Predominantly silt, with some sand and gravel.","","","TN002","107","Tanana","Unconsolidated","107","Qc","",""
    "Qta","Talus","Quaternary","Angular boulder rubble in cirque.","","","TN002","159","Tanana","Unconsolidated","107","Qc","","1071"
    "Qh","High-level eolian and colluvial deposits","Pleistocene","Windblown and reworked windblown deposits of silt and very fine sand","","","UL002","111","Unalakleet","Unconsolidated","107","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.
","","","OP005","104","Ophir ","Unconsolidated","107","","",""
    "Qrs","Recent slide and slump deposits","Holocene","Very fresh, unmodified slumps and earthflows (Occurred about 1940).","","","TN002","158","Tanana","Unconsolidated","108","Qls","",""
    "Qls","Older landslide deposits","Quaternary","Slumps and earth and rock slides","","","TN002","108","Tanana","Unconsolidated","108","Qls","",""
    "ls","Landslide deposits","Quaternary?","Not described","","","NL004","108","Nulato","Unconsolidated","108","","",""
    "Qt","None","Quaternary","Terrace alluvium","","","OP002","103","Ophir","Unconsolidated","110","Qt","",""
    "Qt","Terrace deposits","Quaternary","Terrace deposits","","","KT002","101","Kateel River","Unconsolidated","110","Qt","",""
    "Qhs","High terrace and slope deposits","Quaternary","Light-gray and grayish-orange micaceous silt.  Subordinate lenses of sand and peat.","","","KT002","104","Kateel River","Unconsolidated","110","Qt","",""
    "Qbg","Low-level bench gravel of Minook Creek","Quaternary","Gravel and sand on bench along lower parts of Minook and Hunter Creeks","","","TN002","109","Tanana","Unconsolidated","110","Qt","",""
    "Qtr","Terrace deposits","Quaternary","Gravel, silt, and sand near mouth of Fleshlanana Creek","","","TN002","110","Tanana","Unconsolidated","110","Qt","",""
    "Qhs","High-terraces and slope deposits","Quaternary","Light-gray and grayish-orange micaeous silt deposits.  Subordinate lenses of sand and peat.  Deposits form a broad terrace 10 to 100 m above the floodplain of the Koyukuk Flats and extend as much as 250 m up the slopes of the bedrocks hills surrounding the Flats.  Terrace deposits characterized by thermokarst topography marked by many small lakes.  Unit also forms terrace and slope deposits along streams that drain bedrock uplands and locally include coarse-grained colluvial and fan deposits.","","","NL003","110","Nulato","Unconsolidated","110","","",""
    "Qt","Terrace deposits","Quaternary","Terraced alluvial silt deposits with minor peat and gravel","","","CA002","150","Candle","Unconsolidated","110","Qt","",""
    "Qt","Terrace and slope deposits","Holocene and Pleistocene","Terrace and slope deposits","","","NR002","68","Norton Bay","Unconsolidated","110","Qt","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels","","","SE004","401","Selawik","Unconsolidated","110","","","1100"
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.
","","","CA003","3150","Candle","Unconsolidated","110","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.","","","KT004","104","Kateel River ","Unconsolidated","110","","",""
    "Qua","Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels","","","NL004","410","Nulato","Unconsolidated","110","","",""
    "Qfo","Older flood-plain deposits","Quaternary","Chiefly light-gray and grayish-orange micaeous silt.  Locally include peat, reworked eolian sand and gravel.  Deposits at or near river level but youthful flood-plain features are much modified or absent.  Contact with Qfy locally gradational and poorly defined.","","","MZ002","130","Melozitna","Unconsolidated","111","Qac","",""
    "Qfo","Older floodplain deposits","Quaternary","Chiefly light-gray and grayish-orange micaceous silt.  Locally includes peat, reworked eolian sand, and gravel","","","KT002","103","Kateel River","Unconsolidated","111","Qac","",""
    "Qfy","Younger flood-plain deposits","Quaternary","Silt, sand, and gravel","","","MD002","101","Medfra","Unconsolidated","111","Qac","",""
    "Qfo","Older flood-plain deposits","Quaternary","Largely silt and sand but probably includes abundant gravel along Tonzona River.","","","MD002","102","Medfra","Unconsolidated","111","Qac","",""
    "Qfo","Older flood-plain deposits","Quaternary","Cheifly light-gray and grayish-orange micaeous silt.  Subordinate lenses of sand and peat, reworked eolian sand, and gravel.  Deposits are at or near river level but youthful floodplain features such as oxbow lakes, meander scrolls, and abandoned channels are much modified or absent.","","","NL003","111","Nulato","Unconsolidated","111","","",""
    "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","MD004","101","Medfra","Unconsolidated","111","","",""
    "Qf","Flood-plain and estuarine deposits","Holocene","Flood-plain and estuarine deposits","","","NR002","24","Norton Bay","Unconsolidated","116","Qes","",""
    "Qf","Flood-plain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt","","","NR003","9","Norton Bay","Unconsolidated","116","Qes","",""
    "Qna","Nogahabara sand dunes -- active dunes","Quaternary","Active dunes.  Circular body, nearly 5 mi in diameter.  Entriely sand, free of vegetation cover.","","","KT002","110","Kateel River","Unconsolidated","119","Qd","","1190"
    "Qs","Sand","Quaternary","Eolian sand deposits of the Kobuk Sand Dunes","","","BM002","104","Baird Mountains","Unconsolidated","119","Qd","","1190"
    "Qsa","Actively drifting and recently stabilized dune fields ","Holocene","Fine- to coarse-grained sand","","","KT004","900","Kateel River ","Unconsolidated","119","","","1190"
    "Qsa","Actively drifting and recently stabilized dune fields","Holocene","Great Kobuk and Little Kobuk Sand Dunes in the southwestern Ambler River and southeastern Baird Mountains quadrangles, and Nogahabara Sand Dunes in the Kateel River quadrangle.   The Great Kobuk and Little Kobuk dune fields covering  24 square miles (65 square kilometers)  and 3 square miles (8 square kilometers), respectively, are composed of parabolic or U-shaped dunes and large transverse dune ridges that locally develop into barchan-like dunes.  Wind direction varies from NE to SE.   Fine- to coarse-grained sand","","","AR003","715","Ambler river","Unconsolidated","119","","","1190"
    "Qms","Modified eolian sand deposits","Quaternary","Dark-yellowish-orange and light-gray, fine- to medium-grained eolian sand.  Forms briad sheetlike dune field mantling older floodplain (Qfo) and alluvial terrace (Qac) deposits of the Dulbi Flats.  Deposits have a strong northeast-southwest trend.","","","MZ002","120","Melozitna","Unconsolidated","120","Qd","",""
    "Qns","Nogahabara sand dunes -- stabilized dunes","Quaternary","Scattered circular and elliptical bodies of eolian sand.","","","KT002","111","Kateel River","Unconsolidated","120","Qd","",""
    "Qms","Modified eolian sand deposits","Quaternary","Dark-yellowish-orange and light-gray, fine- to medium-grained eolian sand.  Forms broad sheet-like dune field mantling alluvial silt deposits of the Koyukuk flats and all but tops of bedrock hills in vicinity of Roundabout Mountain.","","","KT002","112","Kateel River","Unconsolidated","120","Qd","",""
    "Qms","Modified eolian sand deposits","Quaternary","Sheetlike dune fields of tan fine- to medium-grained eolian sand, locally overlain by peat and loess","","","MD002","103","Medfra","Unconsolidated","120","Qd","",""
    "Qess","Sand and silt","Quaternary","Well-sorted sand, commonly in subdued dune forms","","","TN002","120","Tanana","Unconsolidated","120","Qd","",""
    "Qs","Chiefly sand deposits","Quaternary","Modified and dissected deposits of wind-blown and water-laid sand with subordinate amounts of silt","","","SH002","9","Shungnak","Unconsolidated","120","Qd","",""
    "Qs","Chiefly sand deposits","Quaternary","Modified and dissected deposits of wind-blown and water-laid sand with subordinate amounts of silt","","","SE002","120","Selawik","Unconsolidated","120","Qd","",""
    "Qws","Chiefly wind-blown and water-laid silt","Quaternary","Chiefly wind-blown and water-laid silt.  Locally includes glacial outwash.","","","SE002","110","Selawik","Unconsolidated","120","Qd","",""
    "Qs","Eolian deposits","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","SP003","711","Survey Pass","Unconsolidated","120","","",""
    "Qs","Eolian and water-laid sand sheets and sand dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","BT003","112","Bettles","Unconsolidated","120","Qd","",""
    "Qs","Eolian and water-laid sand sheets and dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","AR003","700","Ambler River","Unconsolidated","120","Qd","",""
    "Qs","Eolian and water-laid sand sheets and dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","BM003","1104","Baird Mountains","Unconsolidated","120","Qd","",""
    "Qs","Eolian and water-laid sand sheets and dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","WI003","112","Wiseman","Sedimentary","120","","",""
    "Qs","Eolian and water-laid sand and silt","Quaternary","Eolian and water-laid sand and silt","","","RB009","812","Ruby","Unconsolidated","120","Qs","",""
    "Qs","Chiefly sand deposits","Quaternary","Modified and dissected deposits of wind-blown and water-laid sand with subordinate amounts of silt","","","SE004","402","Selawik","Unconsolidated","120","Qd","",""
    "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields","Holocene and Pleistocene","Modified and partly dissected sheets of mixed wind-blown and water-laid deposits bordering the south edge of the Brooks Range","","","SH004","709","Shungnak","Unconsolidated","120","","",""
    "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields ","Holocene and Pleistocene","Sand and coarse silt. ","","","HU003","120","Hughes ","Unconsolidated","120","","",""
    "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields ","Holocene and Pleistocene","Sand and coarse silt.","","","KT004","112","Kateel River ","Unconsolidated","120","","",""
    "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields ","Holocene and Pleistocene","Sand and coarse silt. ","","","SH004","709","Shungnak","Unconsolidated","120","","",""
    "Ql","Loess","Quaternary","Well-sorted silt","","","TN002","121","Tanana","Unconsolidated","121","Qfl","",""
    "Qg","Glacial drift","Quaternary","Unsorted bouldery till and isolated moraines; may include some younger solifluction deposits near valley sides.","","","MZ002","140","Melozitna","Unconsolidated","125","Qm","",""
    "Qg","Glacial drift","Quaternary","Unsorted bouldery till","","","MD002","104","Medfra","Unconsolidated","125","Qm","",""
    "Qdw","Glacial drfit","Quaternary, probable Wisconsin","Chiefly till and outwash deposits of Walker Lake Glaciation","","","SH002","3","Shungnak","Unconsolidated","125","Qm","",""
    "Qda","Glacial drfit","Quaternary, probable Wisconsin","Chiefly till and outwash deposits of Ambler Glaciation.  Locally includes outwash of Walker Lake Glaciation.","","","SH002","5","Shungnak","Unconsolidated","125","Qm","",""
    "Qg","Glacial deposits","Quaternary","Undifferentiated glacial deposits.","","","BM002","103","Baird Mountains","Unconsolidated","125","Qm","",""
    "Qm","Glacial deposits","Quaternary","Locally mapped glacial deposits","","","TN007","9001","Tanana","Unconsolidated","125","Qm","",""
    "QTgl","Glacial and glaciolacustrine deposits.","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","SP003","703","Survey Pass","Unconsolidated","125","","",""
    "QTgl","Glacial and glaciolacustrine deposits.","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","AR003","702","Ambler River","Unconsolidated","125","Qm","",""
    "QTgl","Glacial and glaciolacustrine deposits.","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","BM003","1103","Baird Mountains","Unconsolidated","125","Qm","",""
    "QTgl","Glacial and glaciolacustrine deposits","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","WI003","111","Wiseman","Sedimentary","125","","",""
    "QTgl","Glacial and glaciolacustrine deposits ","Pleistocene and Pliocene?","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.  Further south, in the Bettles, Hughes, Shungnak. and Selawik quadrangles, the unit is composed of discontinuous areas of highly modified drift of Pliocene? and early Pleistocene age interspersed with alluvium and eolian deposits.  Glacial erratics occur in hilly parts of the central Shungnak and Hughes quadrangles to an elevation of 1,500 feet (600 meters). In the Bettles quadrangle the southern margin of the unit consists chiefly of lacustrine sediments deposited from a large proglacial lake.","","","HU003","125","Hughes ","Unconsolidated","125","","",""
    "QTgl","Glacial and glaciolacustrine deposits ","Pleistocene and Pliocene?","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.  Further south, in the Bettles, Hughes, Shungnak. and Selawik quadrangles, the unit is composed of discontinuous areas of highly modified drift of Pliocene? and early Pleistocene age interspersed with alluvium and eolian deposits.  Glacial erratics occur in hilly parts of the central Shungnak and Hughes quadrangles to an elevation of 1,500 feet (600 meters). In the Bettles quadrangle the southern margin of the unit consists chiefly of lacustrine sediments deposited from a large proglacial lake.","","","TN008","30125","Tanana","Unconsolidated","125","","",""
    "Qt4","Till, Cirque glaciation","Quaternary?","Unsorted boulder to clay-size  particles.  Moraine forms locally present, restricted to cirques","","","TN002","130","Tanana","Unconsolidated","130","Qnd","",""
    "Qt","Till, undifferentiated","Quaternary","Unsorted boulder to clay-size particles, no clear morainic forms.","","","TN002","135","Tanana","Unconsolidated","135","Qwu","",""
    "Qyg","Younger Glacial drift","Pleistocene and recent","Younger Glacial drift of till and outwash gravel and sand","","","HU002","125","Hughes","Unconsolidated","135","","",""
    "Qt3","Till","Quaternary","Unsorted boulder to clay-size particles, includes long low lateral moraine on Halu Creek","","","TN002","136","Tanana","Unconsolidated","136","Qwr","",""
    "Qt2","Till","Quaternary","Unsorted boulder to clay-size particles, lowest moraine on Halu Creek","","","TN002","137","Tanana","Unconsolidated","137","Qw2","",""
    "Qt1","Till","Quaternary?","Unsorted boulder to clay-size particles, farthest down valley moraine on lower Halu Creek.","","","TN002","138","Tanana","Unconsolidated","138","Qw1","",""
    "Qb","Rock-defended terraces on Minook Creek","Quaternary","Erosional benches along east side Minook Creek","","","TN002","160","Tanana","Unconsolidated","160","Qrd","",""
    "Qat","Altiplanation terrace","Quaternary","Flat, even surface, formed on bedrock hilltops generally above 600 m","","","TN002","161","Tanana","Unconsolidated","161","Qat","",""
    "Qga","Undifferentiated older glacial drift and alluvium","Pleistocene and recent","Undifferentiated older glacial drift and alluvium of glacial till and outwash, silt, colluvium, and loess","","","HU002","120","Hughes","Unconsolidated","190","","",""
    "Qga","Undifferentiated older glacial drfit, alluvium, and eolian deposits","Quaternary, Illinoian","Chiefly highly modified till and outwash gravels mantled by wind-blown and water-laid silt and fine sand.","","","SH002","7","Shungnak","Unconsolidated","190","Qog","",""
    "Qga","Undifferentiated older glacial drfit, alluvium, and eolian deposits","Quaternary, Illinoian","Chiefly highly modified till and outwash gravels mantled by wind-blown and water-laid silt and fine sand.","","","SE002","190","Selawik","Unconsolidated","190","Qog","",""
    "QTgl","Glacial and glaciolacustrine deposits","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits. In the Bettles quadrangle the southern margin of the unit consists chiefly of lacustrine sediments deposited from a large proglacial lake.","","","BT003","111","Bettles","Unconsolidated","190","Qog","",""
    "QTg","Gravel deposits on Jones Creek","Quaternary-Tertiary","Moderately dipping gravel exposed on Jones Creek near Nixon Fork fault, approximately 25 m thick","","","MD002","151","Medfra","Unconsolidated","285","QTg","",""
    "QTg","High-level gravel","late Tertiary or early Quaternary","Well packed gravel, caps hills in vicinity of Rampart","","","TN002","285","Tanana","Unconsolidated","285","QTg","",""
    "QTgr","Quartz gravel deposits","Quaternary/Tertiary","High-level deposits of quartz pebble gravel; overlies basalt flows of unit Tb.","","","BT003","127","Bettles","Unconsolidated","285","QTg","",""
    "QTgr ","Quartz gravel deposits","Quaternary or Tertiary","High-level deposits of quartz pebble gravel; overlies basalt flows of unit Tb. ","","","TN008","30285","Tanana","Unconsolidated","285","","",""
    "Qya","Younger alkalic basalt cones and flows","Pleistocene","More than 40 alkali basalt, basanite, and hawaiite cones, short flows, and maar craters","","","UL002","112","Unalakleet","Igneous","300","","",""
    "Qyt","Younger tholeiitic basalt cones and flows","Holocene (?) and Pleistocene","Black glassy olivine tholeiite basalt flows of well-preserved pahoehoe structure including ropy flow surfaces and lava tubes","","Whole-rock K/Ar age of 0.19+0.02 Ma","UL002","113","Unalakleet","Igneous","305","","",""
    "QTb","Basalt","early Quaternary or late Tertiary","Nearly horizontal flows of vesicular olivine basalt.  Flows extruded over terrain of moderate relief, ranging in elevation from 175 to over 1,600 feet.","","","KT002","500","Kateel River","Igneous","350","QTb","",""
    "QTb","Older basalt flows","Pleistocene and Pliocene","Abundant vesicular tholeiitic and alkali olivine baslt flows which form a broad shield volcano.  Columnar jointed.  Tholeiitic basalt has diktytaxitic texture","","4 whole-rock K/Ar ages of 3.25+0.11 Ma, 2.8+0.1 Ma, 1.99+0.06 Ma, and 1.39+0.04  Ma.","UL002","108","Unalakleet","Igneous","350","","",""
    "QTb","Basalt","Tertiary (?) and Quaternary","Flows of vesicular olivine basalt.  Minor glassy basalt.  Believed to be correlative with Imuruk Volcanics of Bendeleben quad","","","CA002","500","Candle","Igneous","350","QTb","",""
    "QTb","Basalt","Pleistocene or Late Tertiary","Dissected, nearly horizontal flows of gray to dark-red vesicular olivine basalt.","","","SH002","23","Shungnak","Igneous","350","QTb","",""
    "QTb","Basalt","Pleistocene or Late Tertiary","Dissected, nearly horizontal flows of gray to dark-red vesicular olivine basalt.","","","SE002","500","Selawik","Igneous","350","QTb","",""
    "QTb","Basalt","Pleistocene or Pliocene","Basalt","","","NR002","76","Norton Bay","Igneous","350","QTb","",""
    "QTb","Basalt flows ","Pleistocene and Pliocene","Vesicular tholeiitic and alkali basalt flows. In Candle and Selawik quadrangles unit includes several alkali basalt cones and flows that contain abundant peridotite inclusions.

","","K/Ar isotopic cooling ages from the volcanic field in western part of Unalakleet quadrangle range  from 3.25 Ma to 1.39 Ma.","CA003","500","Candle","Igneous","350","","",""
    "QTa","Andesitic lava","Late Tertiary or early Quaternary","Light to very light-gray vesicular lava.  Removed from final map","","","TN002","451","Tanana","Igneous","451","QTa","",""
    "Ts","Sandstone, Claystone, Conglomerate, and Lignite","Tertiary","Grayish-white granule conglomerate and sandstone, reddish-brown claystone, and lignite coal.  Exposed at river level at the ""Palisades"" along the Yukon River.","Pollen of probable Miocene age.","","MZ002","200","Melozitna","Sedimentary","640","Tcb","",""
    "Ts","Sedimentary rocks","early Tertiary and Miocene","Interbedded polymictic pebble-cobble-boulder conglomerate, grit, and sandstone, with siltstone, shale, and lignite.","","","TN002","640","Tanana","Sedimentary","640","Tcb","",""
    "Ts","Sedimentary rocks, undivided","Tertiary, Eocene","Interbedded polymictic pebble-cobble-boulder conglomerate, grit, and sandstone, with siltstone, shale, and lignite.","","","TN003","640","Tanana","Sedimentary","640","Tcb","",""
    "Ts","Clay shale and coal","Miocene or Oligocene","Poorly consolidated deposits of gray to brown clay shale, lignitic coal, and yellow volcanic ash","Pollen and spore assemblages from lignite (Seldovian age)","","UL002","123","Unalakleet","Sedimentary","640","","",""
    "Ts","Shale, sandstone, and coal","Miocene? or Oligocene?","Shale, sandstone, and coal","","","NR002","396","Norton Bay","Sedimentary","640","Tcb","",""
    "Ts","Gravel and sand","Tertiary","A small cutbank exposure of moderately dipping gravel and sand at north edge of Selawik Hills on eastern tributary of Mangoak River.  Composed chiefly of poorly sorted granitic rock detritus that appears to have been derived from nearby granitic rocks","","","SE002","1320","Selawik","Sedimentary","640","","",""
    "Ts","Small deposits of nonmarine conglomerate, sandstone, shale, and coal ","Tertiary","Poorly consolidated nonmarine deposits.  In the Melozitna and Tanana quadrangles consist of sandstone, claystone, conglomerate, and lignite exposed on south bank of Yukon River near the border of the Melozitna and Tanana quadrangles and small outcrops on the north side of the Yukon River in the Tanana quadrangle located close to the Kaltag Fault.  Elsewhere in the Tanana quadrangle consist of sandstone, shale, coal, and lignite exposed on the Tozitna River and its tributaries in central part of Tanana quadrangle.","Pollen samples from these five areas range in age from Oligocene to Pliocene. ","","TN008","30640","Tanana","Unconsolidated","640","","",""
    "none","Fault zone rocks","Tertiary or older","Rocks within major fault zones; may be cataclastic or mylonitic, variable ages depending on fault and country rocks","","","TN007","9002","Tanana","Unconsolidated","999","fg","",""
    "Tvs","Rhyolitic volcanic and sedimentary rocks","Tertiary?","Rhyolitic lava and breccia.  Tuff and welded tuff common.  Cherty rocks minor, thin-bedded or in nodules.","","","TN002","1001","Tanana","Igneous","1001","Trs","",""
    "Tv","Volcanic rocks, undivided","Paleocene to Eocene","Bimodal assemblage of rhyolite and banded rhyolite flow rocks, rhyolitic breccia, tuffaceous sedimentary rocks, and amygdaloidal basalt flow rocks.","","","TN003","1001","Tanana","Igneous","1001","Trs","",""
    "Tr","Rhyolite and dacite","Eocene","Composed of finely banded flows, tuffs, breccias, and hypabyssal domal intrusive bodies","","Two samples with K-Ar ages, one yielded 50.6 +/- 1.5 on biotite and 47.6 +/- 1.4 hornblende, the other 53.3 +/- 1.6 biotite and 49.1 +/- 1.5 hornblende","NL003","201","Nulato","Igneous","1002","","",""
    "Td","Rhyolite domes and flows","Eocene or Paleocene","Well exposed erosional remnants of rhyolite domes and flows and associated basal breccia and tuff","","K/Ar age of 56.0+1.7 Ma from sanidine","UL002","120","Unalakleet","Igneous","1002","","",""
    "Kv","Andesitic volcanic rocks","Early Cretaceous","Andesitic crystal-bearing lithic tuff and tuff breccia; probably correlative with andesitic volcanic rocks of Neocomian age in Hughes quad (Patton and Miller, 1966)","","","BT002","135","Bettles","Igneous","1002","Kve","",""
    "TKv","Volcanic rock","Tertiary","Indian River, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia.  Subordinate pumice, dark vitrophyre, and obsidian.  Reassigned to Tertiary by Patton (1998), separated from Takhakhdona Hills by Patton (2000)","Obsidian chippings and artifacts found in archeological site in NW AK may have source in obsidian occurrence north of Little Indian River.","Flows in Tanana and Bettles quads have K-Ar date of 58 m.y.","MZ004","210","Melozitna","Igneous","1002","Trs","",""
    "Td","Dacite and rhyolite lava flows, domes, and volcaniclastic rocks","Eocene and Paleocene","Finely banded dacitic and rhyolitic lava flows, basal breccia, tuffs, obsidian, and hypabyssal domal intrusive bodies. Spatially associated with andesite and basalt unit (Ta) and forms a compositionally continuous suite with unit Ta. ","","K/Ar  isotopic cooling ages range from 60 to 40 Ma.","TN008","31002","Tanana","Igneous","1002","","",""
    "QTb","Basalt","Quaternary or Tertiary","Horizontal flows of dark vesicular to massive olivine basalt; subordinate volcanic conglomerate and breccia ","","","BT002","105","Bettles","Igneous","1004","QTb","",""
    "Tb","Basalt flows ","Oligocene","Vesicular and columnar-jointed basalt flows and lahar deposits. ","","Unit yielded a K/Ar cooling age of 32 Ma.","TN008","30350","Tanana","Igneous","1004","","",""
    "Thr","Hypabyssal rhyolite","Eocene or Paleocene","Fine-grained porphyritic hyabyssal rhyolite.","","","UL002","122","Unalakleet","Igneous","1011","","",""
    "TKv","Felsic volcanic rocks","Tertiary and Cretaceous (?)","Brown, gray, and light-tan porphyritic flows, breccia, conglomerate, and tuff of acidic and intermediate composition","","K/Ar age of 58 =?- 1.7 m.y.","BT002","110","Bettles","Sedimentary","1081","Tda","",""
    "Tad","Andesite and basalt lava flows and volcaniclastic rocks (Ta) and dacite and rhyolite lava flows, domes, and volcaniclastic rocks (Td), undivided ","Eocene and Paleocene","Confined to west-central part of Melozitna quadrangle where field data are insufficient to map units Ta and Td separately.","","","MZ004","4210","Melozitna","Igneous","1081","","",""
    "TKv","Volcanic rock","Tertiary to Late Cretaceous","Indian River, Takhakhdona Hills, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia.  Subordinate pumice, dark vitrophyre, and obsidian.  In Takhakhdona Hills also includes dark-green to black vesicular basalt flows.  Big Creek- dark-green to green dacite and andesite porphyry flows and crystal tuffs.  Probably correlative with similar flows and tuffs in Tanana and Bettles quads.  Basalt and andesite flows reassigned to Tertiary by Patton (1998)","Obsidian chippings and artifacts found in archeological site in NW AK may have source in obsidian occurrence north of Little Indian River.","Flows in Tanana and Bettles quads have K-Ar date of 58 m.y.","MZ002","220","Melozitna","Igneous","1103","Tvab","",""
    "Ta","Andesite and basalt flows","Eocene and Paleocene","Columnar-jointed andesite and basalt flows.  Andesite dominant, basalt much less common.","","","NL003","200","Nulato","Igneous","1103","","",""
    "Ta","Andesite and basalt flows","Eocene and Paleocene","1,500 m exposure of subaerial columnar-jointed andesite and basalt flows","","K/Ar age of 65.2+3.9 Ma  from hornblende in the base of the unit.  Whole-rock K/Ar age of 51.9+1.6 Ma from the top of the unit.","UL002","119","Unalakleet","Igneous","1103","","",""
    "KJv","Andesitic volcanic rocks - Roundabout Mountain volcanic field","Cretaceous and Jurassic(?)","Chiefly porphyritic pyroxene andesite and trachyandesite flows, andesitic crystal and lithic tuff, and massive andesite breccia, agglomerate, and conglomerate.  Commonly altered and therefore pale green.  Interbedded dark-greenish-gray tuffaceous graywacke, chert, shale, and impure limestone containing Buchia.  Mildly deformed and unaltered vesicular basalt and associated pyroclastic rocks along Koyukuk River near Roundabout Mt. may be of Tertiary age.","","","KT004","801","Kateel River","Igneous","1103","Tvab","",""
    "Ta","Andesite and basalt","Eocene","Andesite and basalt","","","NR002","12","Norton Bay","Igneous","1103","Tvab","",""
    "TKv","Volcanic rock","Tertiary","In Takhakhdona Hills dark-green to black vesicular basalt flows.","","","MZ004","4220","Melozitna","Igneous","1103","Tvab","",""
    "Ta","Andesite and basalt flows","Eocene and Paleocene","1,500 m exposure of subaerial columnar-jointed andesite and basalt flows","","K/Ar age of 65.2+3.9 Ma  from hornblende in the base of the unit.  Whole-rock K/Ar age of 51.9+1.6 Ma from the top of the unit.","UL003","205","Unalakleet","Igneous","1103","","",""
    "Ta","Andesite and basalt lava flows and volcaniclastic rocks ","Eocene and Paleocene","Subaerial, columnar-jointed, andesite and basalt lava flows that locally contain interbedded tuffs, breccias, and agglomerates.  Lava flows composed chiefly of pyroxene andesite and less commonly of hornblende-bearing high-silica andesite, olivine-bearing basaltic andesite, and  basalt.  Upper part of unit locally underlies and is intruded by dacite and rhyolite of unit Td. ","","K/Ar isotopic cooling ages range from 65 to 52 Ma. ","TN008","31103","Tanana","Igneous","1103","","",""
    "Ta","Andesite and basalt lava flows and volcaniclastic rocks","Eocene and Paleocene","Subaerial, columnar-jointed, andesite and basalt lava flows that locally contain interbedded tuffs, breccias, and agglomerates.  Lava flows composed chiefly of pyroxene andesite and less commonly of hornblende-bearing high-silica andesite, olivine-bearing basaltic andesite, and  basalt.  Upper part of unit locally underlies and is intruded by dacite and rhyolite of unit Td","","K/Ar isotopic cooling ages range from 65 to 52 Ma","OP005","5201","Ophir","Igneous","1103","","",""
    "Tt","Tuff and tuff  breccia","Eocene or Paleocene","1,000 m of (1) green intercaldera tuff and tuff breccia, (2) white rhyolite breccia, domes, and ash, (3) highly altered green andesite and dacite flows, and (4) minor pink granite dikes.  500 m of section consists of the green intercaldera tuff and tuff breccia","","","UL002","124","Unalakleet","Igneous","1120","","",""
    "Tg","Granite","early Tertiary","Light-gray biotite granite, only at Manley Hot Springs","","K-Ar(?) 62 Ma","TN002","2470","Tanana","Igneous","1320","Tpgr","",""
    "Tg","Granite","Eocene or Paleocene","Stock composed of pink to light-gray granite and quartz monzonite.  Fine-grained hypidiomorphic granular or sparsely porphyritic granitic rocks characterized by  plagioclase laths","","K/Ar age of 56.2+1.7 Ma from biotite","UL002","121","Unalakleet","Igneous","1320","","",""
    "TKs","Tuff, sandstone, conglomerate, and shale","Early Tertiary and Late Cretaceous","Nonmarine sedimentary rocks rich in volcanic components.  In central part of quadrangle, unit consists of quartz-rich sandstone, conglomerate, siltstone, tuff, tuff breccia, and locally abundant carbonized plant debris.  In southeast part of quadrangle, unit consists of quartz-chert-pebble conglomerate, sandstone, and siltstone containing abundant plant fossils and thin coaly layers","","","UL002","117","Unalakleet","Sedimentary","1510","","",""
    "TKe","Extrusive rocks","Cretaceous or Tertiary ","Basaltic, andesitic, and rhyolitic flows, tuffs, and breccias, and a few dacite flows; interbedded  sandstone and shale.  Flows commonly porphyritic and gently dipping. Probably greater than 500 feet thick.","","","RB002","202","Ruby","Igneous","1600","TKvr","",""
    "TKv","Volcanics","Early Tertiary  and Late Cretaceous","Volcanics","","","OP002","201","Ophir","Igneous","1600","TKv","",""
    "TKv","Volcanic rocks of Nixon Fork-Upper Sulukna River area","Latest Cretaceous, earliest Tertiary","Sills, dikes, flows, and plugs of rhyolite, dacite, and trachyandesite.","","62-67 Ma","MD002","206","Medfra","Igneous","1600","TKnf","",""
    "TKv","Extrusive rocks","Cretaceous  or Tertiary ","Basaltic, andesitic, and rhyolitic flows, tuffs, and breccias, and a few dacite flows; interbedded  sandstone and shale.  Flows commonly porphyritic and gently dipping. Probably greater than 500 feet thick.  (Description from RB002, should match on this map.)","","","RB003","202","Ruby","Igneous","1600","TKvr","",""
    "TKu","Rhyolite, dacite, andesite, and basalt","Early Tertiary and Late Cretaceous","Volcanic and hypabyssal rocks of uncertain composition and age","","","UL002","118","Unalakleet","Igneous","1600","","",""
    "TKva","Basaltic andesite, basalt, and lapilli tuff","Tertiary(?) and Cretaceous","Medium-greenish-gray, aphanitic to fine-grained, porphyritic, hornblende-rich basaltic andesite; uncommon basalt and very fine grained lapilli tuff(?)","","","OP003","1600","Ophir","Igneous","1600","TKv","",""
    "TKad","Andesite and basalt lava flows and volcaniclastic rocks (TKa) and dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks (TKd), undivided","early Tertiary and Late Cretaceous","Andesite and basalt lava flows and volcaniclastic rocks (TKa) and dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks (TKd), undivided","","","UL003","202","Unalakleet","Igneous","1600","","",""
    "TKs","Tuff, sandstone, conglomerate, and shale","Early Tertiary and Late Cretaceous","Nonmarine sedimentary rocks rich in volcanic components.  In central part of quadrangle, unit consists of quartz-rich sandstone, conglomerate, siltstone, tuff, tuff breccia, and locally abundant carbonized plant debris.  In southeast part of quadrangle, unit consists of quartz-chert-pebble conglomerate, sandstone, and siltstone containing abundant plant fossils and thin coaly layers  Unit lumped from proposed I-map (UL002) in overlying extrusive rocks.","","","UL003","3117","Unalakleet","Sedimentary","1600","","",""
    "TKu","Rhyolite, dacite, andesite, and basalt","Early Tertiary and Late Cretaceous","Dacite, rhyolite, and trachyandesite lava flows, domes, sills, dikes, and interlayered breccias and tuffs.  Composed of phenocrysts of  plagioclase, quartz, sanidine, and biotite in a groundmass of quartz and feldspar.  Locally in Unalakleet and Medfra quadrangles, tuffs at the base of unit contain interbeds of quartz- chert-pebble conglomerate, sandstone, siltstone, and thin coaly layers with abundant plant fossils","Palynoflora collected from coaly layers at the base of the unit in the Medfra quadrangle are latest Cretaceous (Campanian or Maastrichtian)  in age","K/Ar isotopic cooling ages for this unit  range from 71 to 53 Ma","UL003","206","Unalakleet","Igneous","1600","","",""
    "TKv","Volcanic and sedimentary rocks","Tertiary? and or Cretaceous","Porphyritic basalt, andesite, and rhyolite flows, tuffs, and breccias with minor intercalated siltstone and sandstone.  Unit widespread south of the Poorman Fault, volcanic rocks and tuff in Spruce Creek  and Main Creek north of the fault probably correlative","","","RB005","120","Ruby","Igneous","1600","","",""
    "TKd","None","Early Tertiary  and Late Cretaceous","Dikes and subvolcanic rocks","","","OP002","204","Ophir","Igneous","1601","TKd","",""
    "Khi","Hypabyssal intrusive rocks","Cretaceous","Small bodies of hypabyssal intrusive rocks including latite and quartz latite porphyry","","","HU002","195","Hughes","Igneous","1602","","",""
    "Khe","Felsic hypabyssal and extrusive rocks","Cretaceous(?)","Small widely scattered bodies of fine-grained intrusive and extrusive rocks including soda rhyolite, quartz latite porphyry, sanidine trachyte, and quartz diorite.  Some welded tuff at eastern end of Selawik Hills.","","","SE002","2210","Selawik","Igneous","1602","TKvr","",""
    "TKi","Shallow intrusive rocks of silicic and intermediate composition","Tertiary and Cretaceous","Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, trachyite, and andesite plugs, domes, sills, and dikes and larger more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry","","","BT003","129","Bettles","Igneous","1602","TKgp","",""
    "TKi","Felsic hypabyssal and extrusive rocks","Cretaceous(?)","Small widely scattered bodies of fine-grained intrusive and extrusive rocks including soda rhyolite, quartz latite porphyry, sanidine trachyte, and quartz diorite.  Some welded tuff at eastern end of Selawik Hills.","","","SE004","3010","Selawik","Igneous","1602","TKvr","",""
    "Khe","Felsic hypabyssal and extrusive rocks","Cretaceous(?)","Small widely scattered bodies of fine-grained intrusive and extrusive rocks including soda rhyolite, quartz latite porphyry, sanidine trachyte, and quartz diorite.  Some welded tuff at eastern end of Selawik Hills.","","","SE004","3010","Selawik","Igneous","1602","TKvr","",""
    "TKnr","Volcanic rocks of the Nowitna River area -- rhyolite","Latest Cretaceous, earliest Tertiary","Altered rhyolite domes and associated rhyolitic tuff and breccia.","","","MD002","201","Medfra","Igneous","1603","TKnr","",""
    "TKs","Volcanic rocks of the Sischu Mountains","Latest Cretaceous, earliest Tertiary","Light-gray to purplish-red banded rhyolite and dacite subaerial flows and domes, locally containing interlayered breccia and tuff.","","66-71 Ma","MD002","207","Medfra","Igneous","1603","TKvs","",""
    "TKsc","Conglomerate, sandstone, and lignite","Latest Cretaceous, earliest Tertiary","Conglomerate, sandstone, and lignite.  Lumped in overlying volcanic unit.","","","MD002","209","Medfra","Sedimentary","1603","TKcg","",""
    "TKr","Rhyolite and dacite","Early Tertiary and Late Cretaceous","Erosional remnants of rhyolite and dacite domes, sills, dikes, and tuffs that are widely distributed throughout the quad.  The rhyolite and dacite of this unit are associated spatially with andesite and basalt flows of unit TKa","","K/Ar ages of 69.1+2.1 Ma and 53.2+1.6  Ma from sanadine, 66.8+2 Ma from hornblende, and 66.4+2 Ma from biotite","UL002","116","Unalakleet","Igneous","1603","","",""
    "TKi","Shallow intrusive rocks","early Tertiary and Late Cretaceous","Shallow intrusive rocks of silicic and intermediate composition.","","","NR002","75","Norton Bay","Igneous","1603","TKi","",""
    "TKd","Dacite and rhyolite flows, volcaniclastic and hypabyssal rocks","Tertiary/Cretaceous","Dacite, rhyolite, and trachyandesite lava flows, domes, sills, dikes, and interlayered breccias and tuffs.  Composed of phenocrysts of  plagioclase, quartz, sanidine, and biotite in a groundmass of quartz and feldspar","Palynoflora collected from coaly layers at the base of the unit in the Medfra quadrangle are latest Cretaceous (Campanian or Maastrichtian)  in age","K/Ar isotopic cooling ages for this unit  range from 71 to 53 Ma","BT003","136","Bettles","Igneous","1603","TKvr","",""
    "TKd","Extrusive rocks","Tertiary and or Cretaceous","Dacite and rhyolite flows, domes, and volcaniclastic and hypabyssal rocks","","","RB009","814","Ruby","Igneous","1603","TKd","",""
    "TKd","Dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks","early Tertiary and Late Cretaceous","Columnar-jointed andesite, basaltic andesite, and basalt lava flows.  Composed of phenocrysts of plagioclase and pyroxene in a fine-grained  groundmass of plagioclase microlites, granular pyroxene, and dark glass","Palynoflora collected from coaly layers at the base of the unit in the Medfra quadrangle are latest Cretaceous (Campanian or Maastrichtian)  in age","K/Ar isotopic cooling ages range from 64 to 54 Ma","UL003","204","Unalakleet","Igneous","1603","","",""
    "TKv","Volcanic rocks","Late Cretaceous and Early Tertiary","Dacite flows, may include tuff and andesite.","","","TN002","1604","Tanana","Igneous","1604","TKvd","",""
    "TKv","Volcanic rocks","Late Cretaceous to Early Tertiary","Dacite flows, may include tuff and andesite.","","","TN003","1604","Tanana","Igneous","1604","TKvd","",""
    "TKn","Volcanic rocks of the Nowitna River area","Latest Cretaceous, Earliest Tertiary","Chiefly subaerial flows of trachyandesite, basaltic andesite, and basalt.  Subordinate intercalated flows and tuffs of rhyolite and dacite.","","63 to 64 Ma","MD002","202","Medfra","Igneous","1605","TKvn","",""
    "TKa","Andesite and basalt","Early Tertiary and Late Cretaceous","Chiefly hornblende andesite, andesite, and basalt lava flows that are widely distributed.  Flows are spatially associated with rhyolite and dacite of TKr","","K/Ar ages of 64.4+1.9 Ma, 61.5+1.8 Ma, and 53.8+1.6 Ma","UL002","114","Unalakleet","Igneous","1605","","",""
    "TKv","Volcanic and Sedimentary rocks","Tertiary (?) and/or Cretaceous (?)","Porphyritic basalt, andesite, and rhyolite flows, tuffs, and breccias with minor intercalated siltstone and sandstone","","","RB004","120","Ruby","Igneous","1605","TKvi","",""
    "TKa","Andesite and basalt flows and volcaniclastic rocks","Tertiary and Cretaceous","Columnar-jointed andesite, basaltic andesite, and basalt lava flows.  Composed of phenocrysts of plagioclase and pyroxene in a fine-grained  groundmass of plagioclase microlites, granular pyroxene, and dark glass","","K/Ar isotopic cooling ages range from 64 to 54 Ma","AR003","710","Ambler River","Igneous","1605","TKvi","",""
    "TKa","Andesite and basalt flows and volcaniclastic rocks","Tertiary and or Cretaceous","Andesite and basalt flows and volcaniclastic rocks","","","RB009","813","Ruby","Igneous","1605","TKa","",""
    "Kh","Hypabyssal rocks","Cretaceous","Small bodies of primarily dacite and rhyolite porphyry.  These intrusives are widespread in volcanic graywacke and mudstone unit (Kgm) and in andesitic rocks (Kv).","","","MZ002","310","Melozitna","Igneous","1620","Kve","",""
    "TKi","Shallow intrusive rocks of silicic and intermediate composition","Early Tertiary and Late Cretaceous","Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, and andesite plugs, domes, sills, and dikes and larger, more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry.","","","NL003","1655","Nulato","Igneous","1620","","",""
    "TKv","Volcanic rock","Tertiary to Late Cretaceous","Indian River, Takhakhdona Hills, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia.  Subordinate pumice, dark vitrophyre, and obsidian.  In Takhakhdona Hills also includes dark-green to black vesicular basalt flows.  Big Creek is dark-green to green dacite and andesite porphyry flows and crystal tuffs.  Probabaly correlative with similar flows and tuffs in Tanana and Bettles quads.  These unit are Tertiary according to Patton (1998) however large area rhyolitic rocks of TKv in the northeastern part of quad. should still be mapped as TKvr","Obsidian chippings and artifacts found in archeological site in NW AK may have source in obsidian occurrence north of Little Indian River.","Flows in Tanana and Bettles quads have K-Ar date of 58 m.y.","MZ002","2210","Melozitna","Igneous","1620","TKvr","",""
    "TKi","Shallow intrusive rocks of silicic and intermediate composition","Early Tertiary and Late Cretaceous","Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, and andesite plugs, domes, sills, and dikes and larger, more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry.","","","NL004","405","Nulato","Igneous","1620","","",""
    "TKc","Mafic to intermediate volcano-plutonic complexes","Early Tertiary  and Late Cretaceous","Mafic to intermediate volcano-plutonic complexes","","","OP002","202","Ophir","Igneous","1630","TKiv","",""
    "TKc","Mafic to intermediate Volcano-plutonic complexes","Latest Cretaceous, earliest Tertiary","Altered basalt, andesite, and trachyandesite porphyry flows and hypabyssal intrusive bodies.  Altered mafic and intermediate crystal and lithic tuffs.  Subordinate olivine basalt and dacite flows.","","K-Ar ages of 65-71 Ma","MD002","204","Medfra","Igneous","1630","TKiv","",""
    "TKvc","Volcano-plutonic complexes ","early Tertiary and Late Cretaceous","Complexes composed primarily of altered basalt, andesite, and trachyandesite porphyry lava flows and hypabyssal intrusive bodies. The complexes also contain altered mafic and intermediate crystal and lithic tuffs and subordinate olivine basalt and dacite flows.  The flows and hypabyssal rocks are composed of plagioclase and clinopyroxene phenocrysts in a groundmass of fine-grained plagioclase laths, granular pyroxene and dark glass. ","","K/Ar isotopic cooling ages  from the unit range from 77 to 65 Ma. ","OP005","202","Ophir ","Igneous","1630","","",""
    "TKvc","Volcano-plutonic complexes ","early Tertiary and Late Cretaceous","Complexes composed primarily of altered basalt, andesite, and trachyandesite porphyry lava flows and hypabyssal intrusive bodies. The complexes also contain altered mafic and intermediate crystal and lithic tuffs and subordinate olivine basalt and dacite flows.  The flows and hypabyssal rocks are composed of plagioclase and clinopyroxene phenocrysts in a groundmass of fine-grained plagioclase laths, granular pyroxene and dark glass. ","","K/Ar isotopic cooling ages  from the unit range from 77 to 65 Ma","MD004","204","Medfra","Igneous","1630","","",""
    "TKi","Mafic and ultramafic intrusive rocks","Cretaceous and (or) Tertiary","Mafic and ultramafic intrusive rocks including pluglike body of augite andesite porphyry and a small dikelike body of augite peridotite","","","HU002","180","Hughes","Igneous","1640","TKum","",""
    "TKsa","","Latest Cretaceous, earliest Tertiary","Dike-like body of dark-brown to gray andesite porphyry.","","","MD002","208","Medfra","Igneous","1641","TKmd","",""
    "TKi","Intrusive rocks","Late Cretaceous(?) or Early Tertiary(?)","Granite, diorite, quartz monzonite, and  may include dikes of varying composition and texture, older intrusives of the greenstone complex (mi), and  hornfelds zones surrounding intrusive rocks.



","","","RB002","201","Ruby","Igneous","1650","TKi","",""
    "TKcm","Mafic to intermediate volcano-plutonic complexes -- monzonite","Latest Cretaceous, earliest Tertiary","Small bodies of monzonite, quartz monzonite, and granodiorite","","","MD002","203","Medfra","Igneous","1650","TKim","",""
    "TKi","Shallow intrusive rocks - Complex","early Tertiary and Late Cretaceous","Shallow intrusive rocks of silicic and intermediate composition.  Complex of many small intrusive bodies","","","NR002","336","Norton Bay","Igneous","1650","TKi","",""
    "Tki","Intrusive Rocks","early Tertiary or Late Cretaceous","Granite and some diorite. Includes numerous dikes and sills and may include hornfels zones","","","NL002","1650","Nulato","Igneous","1655","TKg","",""
    "TKg","Granite","Latest Cretaceous, earliest Tertiary","White to light gray, fine- to coarse-grained biotite granite.","","63-71 Ma","MD002","211","Medfra","Igneous","1655","TKg","",""
    "TKq","Quartz monzonite","Early Tertiary-Late Cretaceous","Light- to vey light-gray quartz monzonite, may range to granite","","K-Ar(?) 61.8 Ma","TN002","1655","Tanana","Igneous","1655","TKg","",""
    "TKg","Granitic rocks, undivided","Late Cretaceous to Early Tertiary","Light- to vey light-gray quartz monzonite, may range to granite.","","K-Ar(?) 61.8 Ma","TN003","1655","Tanana","Igneous","1655","TKg","",""
    "Kg","Granitic rocks","Late Cretaceous?","Granodiorite","","K-Ar date of 81.5 to 89.0 Ma from similar plutons in Melozitna quad., however later data suggests Latest Cretaceous or Early Tertiary age from Nulato quadrangle.","RB004","2410","Ruby","Igneous","1655","TKg","",""
    "TKg","Granite","Cretaceous-Tertiary","Medium- to coarse-grained equigranular to porphyritic biotite granite composed of anhedral quartz, anhedral to euhedral (porphyritic variety) K-feldspar, anhedral plagioclase and subhedral biotite","","K-Ar age of 65.5 +/- 3.3 m.y. from biotite","RB007","110","Ruby","Igneous","1655","TKg","",""
    "TKg","Granite-granodiorite","Tertiary to Cretaceous","Granite-granodiorite","","","RB009","815","Ruby","Igneous","1655","TKg","",""
    "TKg","Granitic rocks","Tertiary and or Cretaceous","Granitic rocks of acidic and intermediate composition.  Cheifly syenite at Roundabout Mountain and albite granite on Huslia River-Derby Creek divide.  Maybe other small unmapped granitic bodies intruding andesitic volcanic rocks in northwestern part of quadrangle","","","KT002","600","Kateel River","Igneous","1655","","",""
    "TKm","None","Early Tertiary  and Late Cretaceous","Monzonite","","","OP002","203","Ophir","Igneous","1660","TKm","",""
    "TKm","Monzonite","Latest Cretaceous, earliest Tertiary","Includes monzonite, quartz monzonite, quartz monzodiorite, and monzodiorite.  Subordinate monzogabbro and gabbro","","66-70 Ma","MD002","205","Medfra","Igneous","1660","TKm","",""
    "TKm","Diorite, monzonite, and quartz syenite","Latest Cretaceous, earliest Tertiary","Light to medium-gray biotite-aegerine-olivine diorite, monzonite, and subordinate quartz syenite.  Forms bulk of Cripple Creek Mountains pluton.","","K-Ar age of 71.3 Ma","MD003","1660","Medfra","Igneous","1660","TKm","",""
    "TKm","Diorite, monzonite, and quartz syenite","Latest Cretaceous, earliest Tertiary","Light to medium-gray biotite-aegerine-olivine diorite, monzonite, and subordinate quartz syenite.  Forms bulk of Cripple Creek Mountains pluton.","","K-Ar age of 71.3 Ma","OP003","1660","Medfra","Igneous","1660","TKm","",""
    "TKm","Monzonite","early Tertiary and Late Cretaceous ","Medium- to coarse-grained, equigranular, biotite and hornblende monzonite, quartz monzonite, monzodiorite, and quartz diorite.  Subordinate monzogabbro and gabbro.","","K/Ar isotopic cooling  ages from this unit range from 70 to 66 Ma.","OP005","203","Ophir ","Igneous","1660","","",""
    "TKm","Monzonite   ","early Tertiary and Late Cretaceous  ","Medium- to coarse-grained, equigranular, biotite and hornblende monzonite, quartz monzonite, monzodiorite, and quartz diorite.  Subordinate monzogabbro and gabbro. ","","K/Ar isotopic cooling  ages from this unit range from 70 to 66 Ma.","MD004","205","Medfra","Igneous","1660","","",""
    "TMg","None","Tertiary or Late Cretaceous (Not designated on map)","Gabbro","","","OP002","205","Ophir","Igneous","1680","TDg","",""
    "TDg","Undifferentiated gabbro","Devonian to Tertiary","Sills, dikes, and small plutons of gabbro intruding rocks of early Paleozoic and preCambrian(?) age","","","MD002","210","Medfra","Igneous","1680","TDgb","",""
    "TDg","Gabbro","Tertiary","Gabbro","","","RB009","816","Ruby","Igneous","1680","TDg","",""
    "TDg","Gabbro and diabase ","Tertiary? to Devonian?","Fresh to altered gabbroic and diabasic intrusive bodies.  Unit intrudes rocks as old as middle Paleozoic and as young as Cretaceous.  May represent a wide range of ages.","","","HU003","2210","Hughes ","Igneous","1680","","",""
    "TDg","Gabbro and diabase","Tertiary? to Devonian?","Fresh to altered gabbroic and diabasic intrusive bodies.  Unit intrudes rocks as old as middle Paleozoic and as young as Cretaceous.  May represent a wide range of ages
","","","OP002","5901","Ophir","Igneous","1680","PzZrqs","",""
    "Klc","Limestone conglomerate","Cretaceous","Pebble to boulder limestone conglomerate, poorly sorted, locally derived, non-marine","plant fossils of Cretaceous age","","CA002","400","Candle","Sedimentary","1815","Kccc","",""
    "Kcc","Carbonate-rich conglomerate and sandstone","Late and Early Cretaceous","Nonmarine and marine carbonate-rich conglomerate and sandstone deltaic deposits.","","","NR002","726","Norton Bay","Sedimentary","1815","Kcc","",""
    "Kcc","Calcareous graywacke and mudstone","Cretaceous","Cyclically interbedded sequence of fine to coarse grained, calcareous graywacke, fine to medium grained carbonaceous, volcanic graywacke, and carbonaceous mudstone.  This unit has been lumped with the eastern part of unit Kcv on the source map and re-labeled (W.W. Patton, Jr., 1999)","abundant carbonized plant debris","","CA002","232","Candle","Sedimentary","1820","Kcvg","",""
    "Kcvg","Carbonaceous volcanic graywacke and mudstone turbidite deposits","Early Cretaceous","Carbonaceous volcanic graywacke and mudstone turbidite deposits","","","NR002","334","Norton Bay","Sedimentary","1820","Kcvg","",""
    "Kcv","Calcareous graywacke and mudstone","Cretaceous","Mixed sequence of calcareous graywacke, calcareous mudstone, volcanic graywacke, and volcanic conglomerate.  Transitional between Kvg and Kcg.  Unit added by Patton, 1999 by sub-division.  Consists of carbonaceous volcanic graywacke and mudstone turbidite deposits.  Much of the eastern part of this unit has been lumped with unit Kcc on the source map and re-labeled (W.W. Patton, Jr., 1999)","abundant carbonized plant debris","","CA003","230","Candle","Sedimentary","1820","Kcvg","",""
    "Kg","Volcaniclastic graywacke and mudstone turbidites","Early Cretaceous","Reassignment of part of unit in extreme northwest part of quadrangle (W.W. Patton, Jr., written commun., 1999).  Dark-gray to green, hard, fine-grained to conglomeratic volcanic graywacke and dark-gray, finely laminated mudstone.  Turbidite assemblage consisting of submarine-fan deposits, chiefly midfan channel, interchannel, and related overbank facies","","","UL003","103","Unalakleet","Sedimentary","1820","","",""
    "Kv","Volcanic graywacke and mudstone","late Early Cretaceous (Albian)","Poorly sorted dark greenish-gray volcanic graywacke and mudstone.  Reclassified in northwestern part of quadrangle from NSA = 2180","","","SH003","17","Shungnak","Sedimentary","1820","Kcvg","",""
    "Kcvg","Carbonate and volcanic clast graywacke and mudstone","late Early Cretaceous (Albian)","Cyclically interbedded fine- to coarse-grained highly calcareous graywacke; hard, fine- to medium-grained, carbonaceous, volcanic graywacke; and dark carbonaceous mudstone.  Graywacke is typically graded and sole-marked. Carbonized plant debris is abundant.  Graywacke/mudstone ratios are generally high. The unit is interpreted to represent middle and outer submarine fan lobe deposits; some locally thick sections of mudstone probably represent basin plain deposits.  Paleocurrents are generally to the northeast.  Unit appears to be transitional between the carbonate-rich deposits of map unit Kcg and the volcanic-rich deposits of map unit Kvg. ","Shallow-water marine mollusks locally abundant but poorly preserved, probably of Early Cretaceous (Albian) age.","","SE004","3004","Selawik","Sedimentary","1820","Kcvg","",""
    "Kcvg","Carbonate- and volcanic-clast graywacke and mudstone submarine fan deposits.","Cretaceous","Cyclically interbedded fine- to coarse-grained highly calcareous graywacke; hard, fine- to medium-grained, carbonaceous, volcanic graywacke; and dark carbonaceous mudstone.  Graywacke is typically graded and sole-marked. Carbonized plant debris is abundant.  Graywacke/mudstone ratios are generally high. The unit is interpreted to represent middle and outer submarine fan lobe deposits; some locally thick sections of mudstone probably represent basin plain deposits.  Paleocurrents are generally to the northeast.  Unit appears to be transitional between the carbonate-rich deposits of map unit Kcg and the volcanic-rich deposits of map unit Kvg. ","Poorly preserved marine mollusks of late Early Cretaceous (?)  age are present in this unit in the Selawik quadrangle","","BM003","1820","Baird Mountains","Sedimentary","1820","Kcvg","",""
    "Kcg","Calcareous graywacke and mudstone","Cretaceous","Rhythmically interbedded, medium-gray, yellowish-orange weathering, fine-grained to gritty highly calcareous graywacke and micaceous, calcareous mudstone.  Abundant carbonized plant debris.  Unit coarsens westward.  Estimated more than 5,000 feet thick.","abundant carbonized plant debris","","CA002","235","Candle","Sedimentary","1821","Kcg","",""
    "Kct","Carbonate-rich sandstone, siltstone, and shale turbidite deposits","Late and Early Cretaceous","Carbonate-rich sandstone, siltstone, and shale turbidite deposits","","","NR002","728","Norton Bay","Sedimentary","1821","Kcg","",""
    "Kcg","Carbonate-clast graywacke and mudstone ","Cretaceous","Fine-grained to gritty graywacke and laminated micaceous mudstone turbidite deposits composed largely of carbonate detritus and lesser amounts of quartz, chert, volcanic rock, and mica clasts.  Contains abundant carbonized plant debris. The mudstone intervals typically display fine, convolute, cross laminations and current rippled partings. Unit grades from a high graywacke/mudstone ratio on the southwest to a low graywacke/mudstone ratio on the northeast; paleocurrent directions are to the northeast. The abundance of detrital carbonate, quartz, and mica fragments suggest that the unit was derived largely from carbonate rocks and schist units (|cs and |<ss), of the Seward terrane.  Unit interpreted to represent submarine mid- to outer-fan deposits.

.
","A single collection of palynomorphs from the Norton Bay quadrangle is Cretaceous in age, possibly late Early or early Late Cretaceous (Albian or Cenomanian). ","","CA003","3230","Candle ","Sedimentary","1821","","",""
    "Kcc","Calcareous graywacke and mudstone","Cretaceous","Poorly sorted nonmarine and shallow-water shelf deposits consisting  of carbonate-rich conglomerate (calcirudite), sandstone (calcarenite), and shale (calcilutite).  Unit contains abundant plant debris and thin seams of bituminous coal.  Clast-supported cobble to boulder conglomerate, composed almost entirely of carbonate rocks, grades eastward into trough cross-bedded, medium- to coarse-grained sandstone and pebble conglomerate fan-delta deposits, which in turn grade eastward into cross-bedded, fine- to coarse-grained, inner and outer shelf sandstone and shale.  Chert, volcanic rock, quartz, and schist detritus present in subordinate amounts. Unit derived in large part from Paleozoic carbonate rocks (Pzcs) of the Seward terrane","abundant carbonized plant debris","","CA003","231","Candle","Sedimentary","1822","Kcc","",""
    "Kcc","Conglomerate facies -- Carbonate-rich conglomerate and sandstone","Late and Early Cretaceous","Conglomerate facies -- Nonmarine and marine carbonate-rich conglomerate and sandstone deltaic deposits.","","","NR002","1816","Norton Bay","Sedimentary","1822","Kcc","",""
    "Kcc","Nonmarine and marine carbonate-rich conglomerate and sandstone deltaic deposits","Late and Early Cretaceous","Poorly sorted nonmarine and shallow-water shelf deposits consisting  of carbonate-rich conglomerate (calcirudite), sandstone (calcarenite), and shale (calcilutite).  Unit contains abundant plant debris and thin seams of bituminous coal.  Clast-supported cobble to boulder conglomerate, composed almost entirely of carbonate rocks, grades eastward into trough cross-bedded, medium- to coarse-grained sandstone and pebble conglomerate fan-delta deposits, which in turn grade eastward into cross-bedded, fine- to coarse-grained, inner and outer shelf sandstone and shale.  Chert, volcanic rock, quartz, and schist detritus present in subordinate amounts. Unit derived in large part from Paleozoic carbonate rocks (Pzcs) of the Seward terrane","","","SE004","3005","Selawik","Sedimentary","1822","Kcc","",""
    "Kcc","Conglomerate facies -- Carbonate-clast conglomerate, sandstone, and shale","Late and Early Cretaceous","Poorly sorted nonmarine and shallow-water shelf deposits consisting  of carbonate-rich conglomerate (calcirudite), sandstone (calcarenite), and shale (calcilutite).  Unit contains abundant plant debris and thin seams of bituminous coal.  Clast-supported cobble to boulder conglomerate, composed almost entirely of carbonate rocks, grades eastward into trough cross-bedded, medium- to coarse-grained sandstone and pebble conglomerate fan-delta deposits, which in turn grade eastward into cross-bedded, fine- to coarse-grained, inner and outer shelf sandstone and shale.  Chert, volcanic rock, quartz, and schist detritus present in subordinate amounts. Unit derived in large part from Paleozoic carbonate rocks (Pzcs) of the Seward terrane","","","NR002","726","Norton Bay","Sedimentary","1822","Kcc","",""
    "Kct","Carbonate-rich sandstone, siltstone, and shale turbidite deposits","Cretaceous","Conglomeritic facies of carbonate-rich sandstone, siltstone, and shale turbidite deposits.","","","NR002","235","Norton Bay","Sedimentary","1823","Kcgc","",""
    "Ksh","None","Late Cretaceous","Shale and siltstone","","","OP002","509","Ophir","Sedimentary","1905","Ksh","",""
    "Ksa","None","Late Cretaceous","Sandstone","","","OP002","508","Ophir","Sedimentary","1906","Ksa","",""
    "Ksu","Shale, siltstone, and sandstone, undivided ","Cretaceous","Chiefly dark carbonaceous, generally nonfossilferous shale, siltstone and fine-grained sandstone.  Poorly exposed except where altered to a dark slaty hornfels in the vicinity of plutonic and hypabyssal intrusive rocks. Locally includes a limestone-clast conglomerate in the central Medfra quadrangle and several volcaniclastic horizons in the Ophir quadrangle.
Unit probably correlative in part with unit Kss of Late Cretaceous age, but some beds may be as old as late Early Cretaceous.","","","OP005","912","Ophir ","Sedimentary","1906","","",""
    "Kvs","None","Late Cretaceous","Volcaniclastic sandstone","","","OP002","507","Ophir","Sedimentary","1907","Kvss","",""
    "Kss","Fine sandstone, siltstone, and shale","early Late Cretaceous (Cenomanian)","Fine- to medium-grained, dark-greenish-gray, thinly cross-bedded, fossiliferous sandstone and poorly exposed dark-gray siltstone and shale.","Inoceramus concentricus, and I. pictus","","MD002","303","Medfra","Sedimentary","1940","uKss","",""
    "Kss","Shallow marine sandstone, siltstone, and shale ","Late Cretaceous","Fine-to medium-grained, thinly cross-bedded, fossiliferous sandstone and poorly exposed dark siltstone and shale.  Clasts composed of 40 to 45 percent quartz, 45 to 50 percent volcanic and sedimentary  lithic fragments, and  5 to 15 percent feldspar, chiefly plagioclase.  Clasts set in a finely divided calcareous and argillaceous matrix. Unit deposited in a nearshore  marine  environment. ","Unit contains abundant early Late Cretaceous (Cenomanian) species of Inoceramus.","","MD004","4303","Medfra","Sedimentary","1940","","",""
    "Ks","Sandstone, Quartz Conglomerate, shale, and siltstone","Probably Late Cretaceous","Non-marine deposits of olive-green, fine- to coarse-grained, crossbedded, quartzose sandstone and grit; quartz-pebble conglomerate, and dark micaeous shale and siltstone.  Ironstone lenses and concretions.  Better sorted and higher percentage of quartz than Kgm.  Probabaly correlative with Upper Cretaceous, plant-bearing nonmarine strata in Kateel River quad.","Abundant carbonized plant debris","","MZ002","330","Melozitna","Sedimentary","1941","Kss","",""
    "Ks","Sandstone, quartz conglomerate, shale, and siltstone, non-marine","Probably Late Cretaceous","Non-marine deposits of olive-green, fine- to coarse-grained, crossbedded, quartzose sandstone and grit; quartz-pebble conglomerate, and dark micaeous shale and siltstone.  Ironstone lenses and concretions.  Better sorted and higher percentage of quartz than Kgm.  Probabaly correlative with Upper Cretaceous, plant-bearing nonmarine strata in Kateel River quad.","Abundant carbonized plant debris","","RB004","1941","Ruby","Sedimentary","1941","Kss","",""
    "Ks","Nonmarine and marine undivided sandstone and shale deltaic deposits","Cretaceous","Nonmarine and marine undivided sandstone and shale deltaic deposits","","","RB009","822","Ruby","Sedimentary","1941","Ks","",""
    "Kls","None","Late Cretaceous","Limy volcaniclastic sandstone","","","OP002","505","Ophir","Sedimentary","1942","Ksl","",""
    "Ku","Undifferentiated clastic rocks","Late Cretaceous","Undifferentiated clastic rocks","","","OP002","502","Ophir","Sedimentary","1970","Kk","",""
    "Ksu","Undifferentiated shale, siltstone, and sandstone","Cretaceous, early and late [possible Permian(?)]","Chiefly dark-gray carbonaceous, largely nonfossiliferous shale, siltstone, and very fine-grained sandstone.  Includes massive limestone conglomerate of uncertain age and stratigraphic affinities.  Conglomerate clasts consist of Paleozoic limestone and unit may be as old as Permian.","reworked Paleozoic","","MD002","301","Medfra","Sedimentary","1970","KPzsu","",""
    "Ksu","Shale, siltstone, and sandstone, undivided","Cretaceous","Chiefly dark carbonaceous, generally nonfossilferous shale, siltstone and fine-grained sandstone.  Poorly exposed except where altered to a dark slaty hornfels in the vicinity of plutonic and hypabyssal intrusive rocks. Locally includes a limestone-clast conglomerate in the central Medfra quadrangle and several volcaniclastic horizons in the Ophir quadrangle.  Unit probably correlative in part with unit Kss of Late Cretaceous age, but some beds may be as old as late Early Cretaceous.","","","MD004","4301","Medfra","Sedimentary","1970","","",""
    "Kss","Fine sandstone, siltstone, and shale","Late Cretaceous","Fine sandstone, siltstone, and shale","","","OP002","504","Ophir","Sedimentary","1971","uKss","",""
    "Kss","Shallow marine sandstone, siltstone, and shale ","Late Cretaceous","Fine-to medium-grained, thinly cross-bedded, fossiliferous sandstone and poorly exposed dark siltstone and shale.  Clasts composed of 40 to 45 percent quartz, 45 to 50 percent volcanic and sedimentary  lithic fragments, and  5 to 15 percent feldspar, chiefly plagioclase.  Clasts set in a finely divided calcareous and argillaceous matrix. Unit deposited in a nearshore  marine  environment","Unit contains abundant early Late Cretaceous (Cenomanian) species of Inoceramus.","","MD004","4302","Medfra","Sedimentary","1971","","",""
    "Ksc","None","Late Cretaceous","Sandstone and conglomerate","","","OP002","503","Ophir","Sedimentary","1985","Kkn","",""
    "Ksc","Sandstone and conglomerate","Late Cretaceous","Chiefly fine- to coarse-grained, greenish-gray to gray, thinly cross-bedded ""salt and pepper"" sandstone and quartz-chert pebble conglomerate.  Poorly exposed interbeds of dark shale and siltstone.","locally abundant plants and fresh and brackish water mollusks","","MD002","302","Medfra","Sedimentary","1985","Kkn","",""
    "Kqc","Quartz-pebble conglomerate","early Late Cretaceous","Small isolated patches of light-gray quartz-pebble conglomerate and quartzose sandstone.  Minor intercalated with light-colored ashy tuff.  Conglomerate almost wholly of quartz and quartzite clasts.  Intruded and thermally altered by granodiorite (Kg)  ","","","MZ002","320","Melozitna","Sedimentary","1990","Kqc","",""
    "Kqc","Quartz-pebble conglomerate","Late Cretaceous","Conglomerate with well rounded clasts of quartz, quartzite, graywacke, chert, schist, and mafic volcanic and intrusive rocks; minor sandstone, shale, and thin ash-fall tuff","Abundant plant fossils","","BT002","115","Bettles","Sedimentary","1990","Kqc","",""
    "Kqc","Quartzitic conglomerate and quartzite","Early or late Early Cretaceous","Light colored, thermally metamorphosed quartz conglomerate and quartzose sandstone and quartzite","","","HU002","135","Hughes","Metamorphic","1990","","",""
    "Kq","Quartz conglomerate, sandstone, and mudstone","Late Cretaceous","Conglomerate composed chiefly of white quartz pebbles in quartzose and micaceous matrix; also has pebbles of phyllite, schist, greenstone, and chert in subordinate amounts.  Interbedded quartzose and micaceous sandstone and mudstone.","","Age based on correlative rocks in the Baird Mtns. and Selawik quadrangles dated by K-Ar.","SH002","13","Shungnak","Sedimentary","1990","Kqc","",""
    "Knc","Nonmarine conglomerate, sandstone, mudstone, and coal","Late Cretaceous","Conglomerate composed chiefly of well-sorted white quartz pebbles in quartzose and micaceous matrix; also has pebbles of phyllite, schist, greenstone, and chert in subordinate amounts.  Interbedded quartzose and micaceous sandstone and mudstone.","Abundant well-preserved plant fossils of probable Cretaceous age","Age based on correlative rocks in the Baird Mtns.and Selawik quadrangles dated by K-Ar.","SE002","210","Selawik","Sedimentary","1990","Kqc","",""
    "Kc","Conglomerate","Cretaceous","Buff to gray, lenticularly bedded, poorly sorted, quartz- and carbonate-rich, pebble and cobble conglomerate; reddish gray, massive to thin bedded, fine- to coarse-grained quartz sandstone; subordinate olive-gray, fossiliferous, mica-rich siltstone, and rare coal lenses.  Well rounded and moderately sorted","Pseudoprotophyllum sp., Castaliites sp., both late Cenomanian","","BM002","201","Baird Mountains","Sedimentary","1990","Kqc","",""
    "Kqc","Quartz-clast conglomerate, sandstone, and shale ","Cretaceous","Composed chiefly of well-sorted and well-rounded clasts of white quartz and/or metagraywacke in a quartzose and micaceous matrix; schist, chert, greenstone, and limestone clasts  occur in subordinate amounts. Conglomerate is interbedded with quartzose, cross-bedded sandstone and carbonaceous and micaceous mudstone.  Contains rare interbeds of ashy tuff.  Plant fossils and thin bituminous coal seams are locally abundant","Sparse plant fossil collections from this unit range in age from late Early Cretaceous to Late Cretaceous","A K/Ar isotopic cooling  age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle","SP003","710","Survey Pass","Sedimentary","1990","","",""
    "Kqc","Quartz-clast congloerate, sandstone, and shale","Cretaceous","Composed chiefly of well-sorted and well-rounded clasts of white quartz and/or metagraywacke in a quartzose and micaceous matrix; schist, chert, greenstone, and limestone clasts  occur in subordinate amounts. Conglomerate is interbedded with quartzose, cross-bedded sandstone and carbonaceous and micaceous mudstone.  Contains rare interbeds of ashy tuff.  Plant fossils and thin bituminous coal seams are locally abundant","Sparse plant fossil collections from this unit range in age from late Early Cretaceous to Late Cretaceous","A K/Ar isotopic cooling age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle","AR003","704","Ambler River","Sedimentary","1990","Kqc","",""
    "Kqc","Quartz and metagraywacke-clast conglomerate, sandstone, and shale","Cretaceous","Composed chiefly of well-sorted and well-rounded clasts of white quartz and/or metagraywacke in a quartzose and micaceous matrix; schist, chert, greenstone, and limestone clasts  occur in subordinate amounts. Conglomerate is interbedded with quartzose, cross-bedded sandstone and carbonaceous and micaceous mudstone.  Contains rare interbeds of ashy tuff.  Plant fossils and thin bituminous coal seams are locally abundant","Sparse plant fossil collections from this unit range in age from late Early Cretaceous to Late Cretaceous","A K/Ar isotopic cooling age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle","WI003","115","Wiseman","Sedimentary","1990","","",""
    "Kqc","Quartz-pebble conglomerate","Late Cretaceous","Conglomerate with well rounded clasts of quartz, quartzite, graywacke, chert, schist, and mafic volcanic and intrusive rocks; minor sandstone, shale, and thin ash-fall tuff","Abundant plant fossils","A K/Ar isotopic cooling age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle","BT003","171","Bettles","Sedimentary","1990","Kqc","",""
    "Knc","Nonmarine conglomerate, sandstone, mudstone, and coal","Late Cretaceous","Conglomerate composed chiefly of well-sorted white quartz pebbles in quartzose and micaceous matrix; also has pebbles of phyllite, schist, greenstone, and chert in subordinate amounts.  Interbedded quartzose and micaceous sandstone and mudstone.","Abundant well-preserved plant fossils of probable Cretaceous age","Age based on correlative rocks in the Baird Mtns.and Selawik quadrangles dated by K-Ar.","SE003","201","Selawik","Sedimentary","1990","Kqc","",""
    "Knc","Nonmarine conglomerate, sandstone, mudstone, and coal","Late Cretaceous","Conglomerate composed chiefly of well-sorted white quartz pebbles in quartzose and micaceous matrix; also has pebbles of phyllite, schist, greenstone, and chert in subordinate amounts.  Interbedded quartzose and micaceous sandstone and mudstone.","Abundant well-preserved plant fossils of probable Cretaceous age","Age based on correlative rocks in the Baird Mtns.and Selawik quadrangles dated by K-Ar.","SE004","3007","Selawik","Sedimentary","1990","Kqc","",""
    "Kqc","Quartz-pebble conglomerate","Late Cretaceous","Conglomerate with well rounded clasts of quartz, quartzite, graywacke, chert, schist, and mafic volcanic and intrusive rocks; minor sandstone, shale, and thin ash-fall tuff","Abundant plant fossils","","WI004","115","Wiseman","Sedimentary","1990","Kqc","",""
    "Kqc","Quartz- and metagraywacke-clast conglomerate, sandstone, and shale ","Cretaceous","Composed chiefly of well-sorted and well-rounded clasts of white quartz and/or metagraywacke in a quartzose and micaceous matrix; schist, chert, greenstone, and limestone clasts  occur in subordinate amounts. Conglomerate is interbedded with quartzose, cross-bedded sandstone and carbonaceous and micaceous mudstone.  Contains rare interbeds of ashy tuff.  Plant fossils and thin bituminous coal seams are locally abundant.  Unit composed chiefly of debris eroded from the Arctic Alaska and Ruby terranes.  Grades downward into unit (Kmc)  reflecting the progressive unroofing of the Arctic Alaska and Ruby terranes beneath the Angayucham-Tozitna terrane.  Unit is regionally metamorposed to stretched-pebble conglomerate, semischist, and phyllite in  northeastern part of the Shungak quadrangle and in adjoining parts of the Ambler River and Hughes quadrangles.","Plant fossils and thin bituminous coal seams are locally abundant. Sparse plant fossil collections from this unit range in age from late Early Cretaceous to Late Cretaceous.","A K/Ar isotopic cooling  age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle.  
","HU003","1990","Hughes","Sedimentary","1990","","",""
    "Kqc","Quartz- and metagraywacke-clast conglomerate, sandstone, and shale ","Cretaceous","Composed chiefly of well-sorted and well-rounded clasts of white quartz and/or metagraywacke in a quartzose and micaceous matrix; schist, chert, greenstone, and limestone clasts  occur in subordinate amounts. Conglomerate is interbedded with quartzose, cross-bedded sandstone and carbonaceous and micaceous mudstone.  Contains rare interbeds of ashy tuff.  Plant fossils and thin bituminous coal seams are locally abundant.  Unit composed chiefly of debris eroded from the Arctic Alaska and Ruby terranes.  Grades downward into unit (Kmc)  reflecting the progressive unroofing of the Arctic Alaska  and Ruby terranes beneath the Angayucham-Tozitna terrane.  Unit is regionally metamorposed to stretched-pebble conglomerate, semischist, and phyllite in  northeastern part of the Shungak quadrangle and in adjoining parts of the Ambler River and Hughes quadrangles.","Plant fossils and thin bituminous coal seams are locally abundant. Sparse plant fossil collections from this unit range in age from late Early Cretaceous to Late Cretaceous.","A K/Ar isotopic cooling  age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle. ","TN008","31990","Tanana","Sedimentary","1990","","",""
    "Ks","Shaktolik Group","late Early Cretaceous to Late Cretaceous","Graywacke, shale, grit, and conglomerate.   Type section on the Shaktolik River approximately 120 miles west of the Ruby quad.  Thickness estimated to be more that 4800 feet along the lower Yukon River.  Unit is obsolete and no longer used.  On map, this area of outcrop was replaced by later mapping.","plant fossils, marine mollusks","","RB002","301","Ruby","Sedimentary","2020","Km","",""
    "Ks","Shaktolik Group","Late Cretaceous","Graywacke, shale, grit, and conglomerate.   Thickness estimated at 4800 feet.  Unit obsolete, no longer shown on map.","Marine mollusks (late Early K) and plant remains (Late K)","","NL002","301","Nulato","Sedimentary","2020","Ksg","",""
    "Ks","Sandstone, shale, and conglomerate","Late Cretaceous","Sandstone, shale, and conglomerate","","","OP002","501","Ophir","Sedimentary","2020","Kme","",""
    "Ks","Nonmarine and marine sandstone, shale, and conglomerate deltaic deposits, undivided","Late and Early Cretaceous","Well-sorted, medium- to coarse-grained, light-olive crossbedded sandstone, fine- to medium-grained drark-gray to green silty sandstone, dark-gray micaceous shale, quart-chert-pebble conglomerate, and thin seams of bituminous coal.  Unit is composed of nonmarine fluvial, delta-plain deposits that grade downward into marine delta-front deposits","","","NL003","1940","Nulato","Sedimentary","2020","","",""
    "Ks","Fluvial and shallow marine sandstone and shale, undivided","Cretaceous","Nonmarine, fluvial, delta-plain deposits that grade downward into marine delta-front deposits. Fluvial deposits are characterized by fine-grained, locally cross-bedded quartzose sandstone interbedded with micaeous shale and siltstone. Near the base, the fluvial beds are composed of fine- to coarse-grained, lenticular, crossbedded, friable sandstone and conglomerate containing pebble- to grit-size clasts of quartz and chert and lesser amounts of mafic intrusive and extrusive rocks, and schist.  Contains bituminous coal seams as much as 3 feet (90 centimeters) in thickness.  Sandstone composed of quartz, chert, metamorphic detritus, and subordinate amounts of volcanic rock fragments.  The quartzose nature of the lithic clasts (including polycrystalline quartz), as well as the relatively high proportions of potassium feldspar and micas suggest a mixed metamorphic and granitic provenance.  These data, when combined with limited paleocurrent data, indicate that the unit prograded westward from a source area in the Ruby terrane bordering the southeastern margin of the Yukon-Koyukuk basin.","Nonmarine fluvial deposits contain abundant fresh- and brackish-water mollusks and well-preserved plant remains of Late Cretaceous (Cenomanian and Turonian?) age.  Shallow marine deposits contain an abundant molluscan fauna of late Early (Albian) and  early Late (Cenomanian) Cretaceous age. 
","","OP005","5501","Ophir ","Unconsolidated","2020","","",""
    "Kn","Nonmarine shale, siltstone and sandstone","Late Cretaceous","Nonmarine deposits of drak-gray to olive-gray micaceous shale and siltstone, and light-olive-gray to yellowish-orange, fine- to coarse-grained, crossbedded sandstone.  Massive sandstone beds near base of unit.  Coarse detrital fraction of sandstone chiefly quartz and chert, feldspar locally abundant.  North of Kateel River, sandstone contains pyroclastic material.  Conglomerate lense near base of quartz and chert.  Coal beds as much as 6 in thick.","Abundant, well preserved flora.","","KT002","210","Kateel River","Sedimentary","2021","Ks","",""
    "Knm","Undifferentiated sedimentary rocks","Cretaceous","Nonmarine, fluvial, delta-plain deposits that grade downward into marine delta-front deposits. Fluvial deposits are characterized by fine-grained, locally cross-bedded quartzose sandstone interbedded with micaeous shale and siltstone. Near the base, the fluvial beds are composed of fine- to coarse-grained, lenticular, crossbedded, friable sandstone and conglomerate containing pebble- to grit-size clasts of quartz and chert and lesser amounts of mafic intrusive and extrusive rocks, and schist.  Contains bituminous coal seams as much as 3 feet (90 centimeters) in thickness.  Sandstone composed of quartz, chert, metamorphic detritus, and subordinate amounts of volcanic rock fragments.  The quartzose nature of the lithic clasts (including polycrystalline quartz), as well as the relatively high proportions of potassium feldspar and micas suggest a mixed metamorphic and granitic provenance","Nonmarine fluvial deposits contain abundant fresh- and brackish-water mollusks and well-preserved plant remains of Late Cretaceous (Cenomanian and Turonian?) age.  Shallow marine deposits contain an abundant molluscan fauna of late Early (Albian) and  early Late (Cenomanian) Cretaceous age","","KT004","212","Kateel River","Sedimentary","2021","Ks","",""
    "Ks","Sandstone, shale, and conglomerate deltaic deposits","Late and Early Cretaceous","Chiefly fluvial and shallow-marine deltaic deposits of well-sorted, medium- to coarse-grained, light-olive crossbedded sandstone, fine- to medium-grained, dark-gray to green silty sandstone, dark-gray micaceous shale, quartz-chert-pebble conglomerate, and thin seams of bituminous coal","Middle Albian to early Cenomanian based on Turrilites acutus, Gastropolites (Gastropolites) kingi, Beaudanticeras (Grantziceras), and Inoceramus sp.; fossil fresh- and brackish-water mollusks; plant fossils, consisting of conifers and angiosperms","K/Ar age of 131 to 158 Ma from detrirtal micas","UL002","104","Unalakleet","Sedimentary","2021","","",""
    "Ks","Sandstone and shale deltaic deposits, undivided","Late and Early Cretaceous","Nonmarine and marine sandstone and shale deltaic deposits, undivided","","","NR002","738","Norton Bay","Sedimentary","2021","Ks","",""
    "Ksc","Undifferentiated sedimentary rocks -- conglomerate facies","Late and Early Cretaceous","Conglomerate facies of sandstone, shale, and conglomerate marine and nonmarine deltaic deposits in southwest part of quadrangle","","","NL004","2024","Nulato","Sedimentary","2021","","",""
    "Ks","Fluvial and shallow marine sandstone and shale, undivided","Cretaceous","Nonmarine, fluvial, delta-plain deposits that grade downward into marine delta-front deposits. Fluvial deposits are characterized by fine-grained, locally cross-bedded quartzose sandstone interbedded with micaeous shale and siltstone. Near the base, the fluvial beds are composed of fine- to coarse-grained, lenticular, crossbedded, friable sandstone and conglomerate containing pebble- to grit-size clasts of quartz and chert and lesser amounts of mafic intrusive and extrusive rocks, and schist.  Contains bituminous coal seams as much as 3 feet (90 centimeters) in thickness.  Sandstone composed of quartz, chert, metamorphic detritus, and subordinate amounts of volcanic rock fragments.  The quartzose nature of the lithic clasts (including polycrystalline quartz), as well as the relatively high proportions of potassium feldspar and micas suggest a mixed metamorphic and granitic provenance.  These data, when combined with limited paleocurrent data, indicate that the unit prograded westward from a source area in the Ruby terrane bordering the southeastern margin of the Yukon-Koyukuk basin.","Nonmarine fluvial deposits contain abundant fresh- and brackish-water mollusks and well-preserved plant remains of Late Cretaceous (Cenomanian and Turonian?) age.  Shallow marine deposits contain an abundant molluscan fauna of late Early (Albian) and  early Late (Cenomanian) Cretaceous age. ","","KT004","210","Kateel River ","Unconsolidated","2021","","",""
    "TKis","Shallow intrusive rocks of silicic and intermediate composition, marine and nonmarine sandstone, shale, and conglomerate, and volcaniclastic graywacke and mudstone turbidite deposits and thermally altered sedimentary rocks","Early Tertiary to Early Cretaceous","Shallow intrusive rocks of silicic and intermediate composition, marine and nonmarine sandstone, shale, and conglomerate, and volcaniclastic graywacke and mudstone turbidite deposits and thermally altered sedimentary rocks","","","NL003","1740","Nulato","Igneous","2023","","",""
    "TKrs","Rhyolite and dacite, and sandstone, shale, and conglomerate deltaic deposits","Early Tertiary and Cretaceous","Hypabyssal rhyolite and dacite (Early Tertiary and Late Cretaceous) that are too small and too numerous to be mapped seperately at this map scale.  Sedimentary host of thermally altered sandstone, shale, and conglomerate","","K/Ar age of 68.8+3 Ma from biotite","UL002","127","Unalakleet","Sedimentary","2023","","",""
    "Kvc","Intricately intruded areas of Volcanic conglomerate and breccia","Early Cretaceous","Intricately intruded areas of Volcanic graywacke and mudstone, late Early Cretaceous (Albian)","","","NR002","337","Norton Bay","Sedimentary","2023","Kvci","",""
    "TKic","Complex of shallow intrusive rocks (TKi) and Cretaceous sedimentary rocks of Yukon-Koyokuk basin","Tertiary to Cretaceous","Complex of shallow intrusive rocks (TKi) and Cretaceous sedimentary rocks of Yukon-Koyokuk basin","","","RB009","817","Ruby","Sedimentary","2023","TKic","",""
    "Kc","Igneous pebble-cobble conglomerate","late Early Cretaceous (Albian) may be as young as Late Cretaceous","Massive poorly sorted conglomerate with pebble to cobble sized clasts primarily of mafic intrusive and extrusive rocks and varied colored chert.  Interbedded with fine-grained to gritty (?) , dark-green to green graywacke and mudstone.  grades upward into sandstone, quartz conglomerate, shale, and siltstone (Ks).  In part overlies and in part laterally gradational with  volcanic graywacke and mudstone (Kgm)","Indeterminate pelecypods","","MZ002","340","Melozitna","Sedimentary","2030","Kcg","",""
    "Kc","Igneous pebble-cobble conglomerate","late Early Cretaceous (Albian) may be as young as Late Cretaceous","Massive poorly sorted conglomerate with pebble to cobble sized clasts primarily of mafic intrusive and extrusive rocks and varied colored chert.  Interbedded with fine-grained to gritty (?) , dark-green to green graywacke and mudstone.  grades upward into sandstone, quartz conglomerate, shale, and siltstone (Ks).  In part overlies and in part laterally gradational with  volcanic graywacke and mudstone (Kgm)","Indeterminate pelecypods","","RB004","2030","Ruby","Sedimentary","2030","Kcg","",""
    "Kic","Igneous pebble-cobble conglomerate","Early Cretaceous","Conglomerate of poorly-sorted clasts of mafic volcanic and intrusive rocks, chert, and graywacke","","","BT002","120","Bettles","Sedimentary","2030","Kcg","",""
    "Kc","Conglomerate","Late(?) and Early Cretaceous","Massive conglomerate of pebble- to boulder-size clasts.  Interbeds of graywacke and mudstone","Leaf impressions","","HU002","150","Hughes","Sedimentary","2030","","",""
    "Kc","Igneous pebble-cobble conglomerate","late Early Cretaceous (Albian)","Massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-sized clasts of mafic extrusive and intrusive rocks in a graywacke and mudstone matrix.","","","SH002","15","Shungnak","Sedimentary","2030","Kcg","",""
    "Kc","Igneous pebble-cobble conglomerate","late Early Cretaceous (Albian)","Massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-sized clasts of mafic extrusive and intrusive rocks in a graywacke and mudstone matrix.","","","SE002","340","Selawik","Sedimentary","2030","Kcg","",""
    "Kmc","Mafic igneous-clast conglomerate, sandstone, and shale","Cretaceous","Consists of massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix.  Clasts predominately mafic intrusive and extrusive rocks, varied colored chert, and locally metagraywacke.  Limestone, quartz, and granitic rock clasts present in subordinate amounts. Conglomerate is interbedded with  mafic- and calcareous-clast  graywacke and mudstone.  Unit composed chiefly of debris eroded from the Angayucham-Tozitna terrane ","","Contains marine mollusks of Early Cretaceous(?) age in the Selawik quadrangle","BT003","116","Bettles","Sedimentary","2030","Kcg","",""
    "Kmc","Mafic igneous-clast conglomerate, sandstone, and shale","Cretaceous","Consists of massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix.  Clasts predominately mafic intrusive and extrusive rocks, varied colored chert, and locally metagraywacke.  Limestone, quartz, and granitic rock clasts present in subordinate amounts. Conglomerate is interbedded with  mafic- and calcareous-clast  graywacke and mudstone.  Unit composed chiefly of debris eroded from the Angayucham-Tozitna terrane ","","Contains marine mollusks of Early Cretaceous(?) age in the Selawik quadrangle","AR003","705","Ambler River","Sedimentary","2030","Kcg","",""
    "Kmc","Mafic igneous-clast conglomerate, sandstone, and shale","Cretaceous","Consists of massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix.  Clasts predominately mafic intrusive and extrusive rocks, varied colored chert, and locally metagraywacke.  Limestone, quartz, and granitic rock clasts present in subordinate amounts. Conglomerate is interbedded with  mafic- and calcareous-clast  graywacke and mudstone.  Unit composed chiefly of debris eroded from the Angayucham-Tozitna terrane ","Contains marine mollusks of Early Cretaceous(?) age in the Selawik quadrangle","","WI003","116","Wiseman","Sedimentary","2030","","",""
    "Kmc","Mafic igneous-clast conglomerate, sandstone, and shale (northern and eastern margin of basin)","Cretaceous","Mafic igneous-clast conglomerate, sandstone, and shale (northern and eastern margin of basin)","","","RB009","821","Ruby","Sedimentary","2030","Kmc","",""
    "Kmc","Igneous pebble-cobble conglomerate","late Early Cretaceous (Albian)","Massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-sized clasts of mafic extrusive and intrusive rocks in a graywacke and mudstone matrix.","Contains marine mollusks of Early Cretaceous(?) age in the Selawik quadrangle","","SE004","3006","Selawik","Sedimentary","2030","Kcg","",""
    "Kmc","Conglomerate","Late(?) and Early Cretaceous","Consists of massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix.  Clasts predominately mafic intrusive and extrusive rocks, varied colored chert, and locally metagraywacke.  Limestone, quartz, and granitic rock clasts present in subordinate amounts. Conglomerate is interbedded with  mafic- and calcareous-clast  graywacke and mudstone.  Unit composed chiefly of debris eroded from the Angayucham-Tozitna terrane ","Leaf impressions","","HU003","216","Hughes","Sedimentary","2030","","",""
    "Kmc","Igneous pebble-cobble conglomerate","late Early Cretaceous (Albian)","Massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-sized clasts of mafic extrusive and intrusive rocks in a graywacke and mudstone matrix.","Contains marine mollusks of Early Cretaceous(?) age in the Selawik quadrangle","","SE004","3006","Selawik","Sedimentary","2030","Kcg","",""
    "Kic","Igneous pebble-cobble conglomerate","Early Cretaceous","Conglomerate of poorly-sorted clasts of mafic volcanic and intrusive rocks, chert, and graywacke","","","WI004","120","Wiseman","Sedimentary","2030","Kcg","",""
    "Kmc","Mafic igneous-clast conglomerate, sandstone, and mudstone","Cretaceous","Consists of massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix.  Clasts predominately mafic intrusive and extrusive rocks, varied colored chert, and locally metagraywacke.  Limestone, quartz, and granitic rock clasts present in subordinate amounts. Conglomerate is interbedded with  mafic- and calcareous-clast  graywacke and mudstone.  Unit composed chiefly of debris eroded from the Angayucham-Tozitna terrane 
Unit stratigraphically underlies unit Kqc. ","Contains marine mollusks  of Early Cretaceous(?)  age in the Selawik quadrangle.   ","","TN008","32030","Tanana","Sedimentary","2030","","",""
    "Km","Marine shale and siltstone","Early Cretaceous","Littorial and offshore marine deposits of dark-gray shale and siltstone interbedded with subordinate dark-greenish-gray fine-grained sandstone in lower part and light-olive fine- to coarse-grained crossbedded sandstone in upper part.  Volcanic conglomerate loccally along contact with andesitic volcanic rocks (unit KJv).  Sandstone generally better sorted and more quartzose than that of units Kgm and Kgs.","Widespread occurrence of Inoceramus altiflummis (McLearn) of Early Cretaceous (Albian) age","","KT002","211","Kateel River","Sedimentary","2101","Ksm","",""
    "Ksm","Marine deltaic deposits","Late and Early Cretaceous","Pale-olive to gray, fine- to coarse-grained, crossbedded, lenticular sandstone grading down into drak-greenish-gray, fine-grasined sandstone and interbedded dark-gray siltstone and shale.","","","NL003","2101","Nulato","Sedimentary","2101","","",""
    "Ksm","Marine deltaic deposts","Early Cretaceous","Marine deltaic deposts","","","NR002","964","Norton Bay","Sedimentary","2101","Ksm","",""
    "Kms","Shallow marine sandstone and shale","Cretaceous","The shallow marine deposits in the lower part of the unit Ks are mapped separately along the Yukon River and in a belt to the west extending from the southern edge of the Norton Bay quadrangle to the western Kateel River quadrangle.  These deposits compose a marine tongue that underlies the fluvial deposits and thickens westward.  On the Yukon River, the marine deposits consist of fine- to coarse-grained, crossbedded, lenticular sandstone grading down into fine-grained sandstone and interbedded dark-gray siltstone and shale.   In the belt to the west, the marine deposits are composed predominantly of siltstone and shale","Shallow marine deposits contain an abundant molluscan fauna of late Early (Albian) and  early Late (Cenomanian) Cretaceous age","","UL003","964","Unalakleet","Igneous","2101","","",""
    "Kms","Fluvial and shallow marine sandstone and shale, undivided","Cretaceous","The shallow marine deposits in the lower part of the unit Ks are mapped separately along the Yukon River and in a belt to the west extending from the southern edge of the Norton Bay quadrangle to the western Kateel River quadrangle.  These deposits compose a marine tongue that underlies the fluvial deposits and thickens westward.  On the Yukon River, the marine deposits consist of fine- to coarse-grained, crossbedded, lenticular sandstone grading down into fine-grained sandstone and interbedded dark-gray siltstone and shale.   In the belt to the west, the marine deposits are composed predominantly of siltstone and shale. ","","","KT004","211","Kateel River ","Unconsolidated","2101","","",""
    "KJcs","Clastic sedimentary rocks","Late Jurassic and Cretaceous","Graywacke sandstone, quartzitic sandstone, quartzite, siltstone, shale, slate, slaty argillite, and polymictic conglomerate.","","","TN002","2105","Tanana","Sedimentary","2105","Kvgm","",""
    "Kgm","Volcanic graywacke and mudstone","late Early Cretaceous (Albian) ","Dark-greenish-gray, fine-grained to gritty(?), poorly sorted graywacke composed largely of first- and second-cycle volcanic debris but locally containing abundant granitic and metamorphic rock debris. Graded bedding common,  Dark gray mudstone interbeds.  Some intercalated crystal tuffs.  Hornfels bordering granodiorite (Kg).  Age based on correlation with HU and KT quads","","","RB004","2105","Ruby","Sedimentary","2105","Kvgm","",""
    "Kv","Volcanic graywacke and mudstone","late Early Cretaceous (Albian)","Poorly sorted dark greenish-gray volcanic graywacke and mudstone.  (Unit replaced by NSA = 1820, per Patton, 2000)","Shallow-water marine mollusks locally abundant but poorly preserved, probably of Early Cretaceous (Albian) age.","","SE002","2105","Selawik","Sedimentary","2105","Kcvg","",""
    "Km","Metasedimentary rocks","late Early Cretaceous (Albian)","Small patches of high-grade metamorphic rocks within Selawik Hills pluton.  Likely to have been of unit Kv in part","","K-Ar age of 110 Ma on biotite from metapelite","SE002","22105","Selawik","Metamorphic","2105","Kvgm","HFS",""
    "Kvm","Volcanic graywacke conglomerate and mudstone","Cretaceous","Volcanic graywacke conglomerate and mudstone","","","KT002","201","Kateel River","Sedimentary","2106","lKvg","",""
    "Kvc","Graywacke sandstone and mudstone -- volcanic conglomerate","Early(?) Cretaceous","Massive volcanic conglomerate mapped within unit or poorly sorted, muddy sandstone (graywacke) interbedded with mudstone.  Conglomerate appears gradational with coarse breccias and agglomerates of andesitic volcanic rocks (unit KJv, KT quad.)","Associated and gradational(?) with units containing Buchia of earliest Cretaceous age.","","KT004","202","Kateel River","Sedimentary","2106","Kvgc","",""
    "Kvc","Volcanic conglomerate and breccia","Early Cretaceous","Massive, poorly stratified pebble to boulder conglomerate, interbedded with dark graywacke and dark finely laminated mudstone.  Unit composed of debris flows and alluvial fan deposits.  Consists chiefly of andesitic volcanic rock detritus, but locally includes notable amounts of granitic and fine-grained tuffaceous material. Unit overlies volcanic breccia and agglomerate of unit Kv of the Koyukuk terrane","","A granitic clast from conglomerate yielded a K/Ar cooling age of 113 Ma","NR002","335","Norton Bay","Sedimentary","2106","Kvc","",""
    "Kcv","Calcareous graywacke and mudstone -- conglomerate","Cretaceous","Conglomeritic facies of a mixed sequence of calcareous graywacke, calcareous mudstone, volcanic graywacke, and volcanic conglomerate.  Transitional between Kvg and Kcg.  An area of unit Kcv in the south west part of the quadrangle has been reassigned by Bill Patton (1999) to the conglomeratic facies of unit Kvc.","abundant carbonized plant debris","","CA003","2281","Candle","Sedimentary","2106","Kvcc","",""
    "Kvc","Volcanic conglomerate and breccia -- conglomerate","Cretaceous","Conglomeritic facies of  volcanic conglomerate and breccia.","","","NR002","231","Norton Bay","Sedimentary","2106","Kvcc","",""
    "Kvc","Volcanic graywacke, conglomerate, and mudstone","Cretaceous","Andesitic volcanic graywacke and mudstone with local amounts of granitic rock detritus and fine-grained tuffaceous material and conglomerate.  Western outcrops of this unit changed to unit conglomeratic facies of unit Kvc by W.W. Patton, Jr. (1999).","","Lead-alpha and K/Ar ages of 90 +/- 10 m.y. to 120 +/- 15 m.y.","CA003","200","Candle","Sedimentary","2106","Kvcc","",""
    "Kvc","Volcanic-clast conglomerate, sandstone, and shale ","Cretaceous","Massive, poorly stratified pebble to boulder conglomerate, interbedded with dark graywacke and dark finely laminated mudstone.  Unit composed of debris flows and alluvial fan deposits.  Consists chiefly of andesitic volcanic rock detritus, but locally includes notable amounts of granitic and fine-grained tuffaceous material. Unit overlies volcanic breccia and agglomerate of unit Kv of the Koyukuk terrane.  Unit stratigaphically overlies unit Kv and underlies unit Kcc.","","A granitic clast from conglomerate yielded a K/Ar cooling age of 113 Ma.","KT004","202","Kateel River ","Sedimentary","2106","","",""
    "Kwc","Wilber Creek unit of Weber and others (1992)","Early Cretaceous","Interlayered siltstone, shale, sandstone, and conglomerate.  Impure graywacke rich in volcanic detritus is locally characteristic and probably correlates with the Kathul Graywacke of the Charley River quadrangle.","","","TN003","2115","Tanana","Sedimentary","2115","Kffg","",""
    "Kwcq","Wilber Creek unit of Weber and others (1992), quartzite","Early Cretaceous","Brown, argillaceous, impure quartzite and graywacke sandstone; locally mappable within dominantly argillaceous and graywacke section.","","","TN003","2118","Tanana","Sedimentary","2115","Kffg","",""
    "Kqc","Quartz-carbonate sandstone and pebbly mudstone","Early Cretaceous (Valanginian, Hauterivian, Barremian, Aptian)","Fine- to coarse-grained quartz-carbonate sandstone and conglomerate, quartzose limestone and dark-gray pebbly mudstone and siltstone.","Buchia sublevis, B. crassicolis, Cylindroteuthis, Inoceramus, Acroteuthis, Tropaeum","","MD002","305","Medfra","Sedimentary","2125","Ksm","",""
    "Kgm","Graywacke sandstone and mudstone","Early Cretaceous","Chiefly medium- to dark-gray mudstone and medium-gray to dark-greenish-gray moderately to highly calcareous fine-grained sandstone..  Sandstone locally contains thin lenses of feldspar and chert grit.  Mudstone commonly banded and finely cross-bedded.","Graptolites of Early Cretaceous age (Albian) age in adjoining Nulato quadrangle.  Not sure what unit though (Ks on pub. map but this doesn't match)","","KT002","201","Kateel River","Sedimentary","2152","Kcs","",""
    "Kcs","Calcareous sandstone, siltstone, and shale turbidite deposits","Early Cretaceous","Fine- to coarse-grained, dark-greenish-gray, moderately to highly calcareous, turbiditic sandstone interbedded with dark-gray shale  and siltstone","","","NL003","303","Nulato","Sedimentary","2152","","",""
    "Kcs","Calcareous sandstone, siltstone, and shale turbidite deposits","Early Cretaceous","Calcareous sandstone, siltstone, and shale turbidite deposits","","","NR002","872","Norton Bay","Sedimentary","2152","Kcs","",""
    "Kcs","Offshore calcareous sandstone, siltstone, and shale ","Cretaceous","Fine- to coarse-grained, moderately to highly calcareous, turbiditic sandstone interbedded with dark-gray shale and siltstone.  The sandstone occurs in beds 20 to 40 inches (50 to 100 centimeters)  thick grading upward into finely cross-laminated, muscovite-rich siltstone and shale.  The bases of sandstone beds commonly are marked by flute casts, ripple marks and rip-up clasts of underlying shale layers along with grit-size grains of quartz and chert.  The siltstone and fine-grained sandstone generally contain thin layers of finely comminuted, carbonized plant debris.  Calcareous discoidal concretions as much as 8 inches  (20 cm) in diameter are common.  The sandstone typically consists of poorly sorted clasts of quartz, chert, feldspar (chiefly plagioclase), muscovite, and carbonate rocks in a carbonate-rich matrix.  Carbonate composes as much as 50 percent of the sandstone. ","Unit contains sparsely distributed ammonites of late Early Cretaceous (Albian) age and is interpreted as a prodelta facies approximately correlative in age with the marine sandstone, siltstone, and shale deltaic deposits of unit Kms.	 ","","KT004","203","Kateel River ","Sedimentary","2152","","",""
    "Ku","Ungalik Conglomerate","Cretaceous","Conglomerate, grit, some graywacke.  Boulders as much as 2 ft in diameter: Sorting and bedding poor.   Believed  to be several hundred ft thick on the Melozitna River north of the Ruby quad.   Patton and Bickel estimate minimum thickness of 1200 feet.  Superceded on later maps.","","","RB002","302","Ruby","Sedimentary","2170","Kuc","",""
    "Ku","Ungalik conglomerate","Creteaceous","Conglomerate, grit, some graywacke.  Clasts are angular to rounded.  Sorting and bedding are poor.  Boulders as much as 2 feet in diameter.  Type section is near the Ungalik River west of Nulato quad.  Thickness believed to be at least several hundred feet.  Unit superceded on later maps","","","NL002","302","Nulato","Sedimentary","2170","Kuc","",""
    "Kgm","Volcanic graywacke and mudstone","late Early Cretaceous (Albian) ","Dark-greenish-gray, fine-grained to gritty(?), poorly sorted graywacke composed largely of first- and second-cycle volcanic debris but locally containing abundant granitic and metamorphic rock debris. Graded bedding common,  Dark gray mudstone interbeds.  Some intercalated crystal tuffs.  Hornfels bordering granodiorite (Kg).  Age based on correlation with HU and KT quads","","","MZ002","350","Melozitna","Sedimentary","2180","Kvgm","",""
    "Kgs","Graywacke sandstone and mudstone","Cretaceous","Poorly sorted, muddy sandstone (graywacke) interbedded with mudstone.  Chiefly dark-greenish-gray to pale-olive tuffaceous and feldspathic, fine- to very coarse-grained sandstone and subordinate dark-gray mudstone.  Abundant lenses of feldspar and chert grit.  Description is such that unit sounds like part of Shaktolik Group.","","","KT002","200","Kateel River","Sedimentary","2180","Kvm","",""
    "Kg","Volcaniclastic graywacke and mudstone turbidite deposits","Early Cretaceous","Dark-gray to green, hard, fine-grained to conglomeratic, volcanic graywacke and dark-gray finely laminated mudstone.  Graywacke composed of  matrix supported intermediate and mafic volcanic and intrusive rock and chert clasts. quartz and metamorphic rock clasts are present in subordinate amounts.  Volcanic clasts dominate lower part of unit, metamorphic clast become increasingly abundant upward","","","NL003","2105","Nulato","Sedimentary","2180","","",""
    "Kvg","Volcanic graywacke, conglomerate, and mudstone","Cretaceous","Andesitic volcanic graywacke and mudstone with local amounts of granitic rock detritus and fine-grained tuffaceous material and conglomerate","","Lead-alpha and K/Ar ages of 90 +/- 10 m.y. to 120 +/- 15 m.y.","CA002","200","Candle","Sedimentary","2180","Kvg","",""
    "Kvg","Volcanic graywacke, conglomerate, and mudstone","Cretaceous","Hard, fine-grained to conglomeratic, locally tuffaceous, graywacke and dark-gray finely laminated mudstone. The graywacke is composed of matrix-supported clasts of intermediate and mafic volcanic and intrusive rocks and chert.  Clasts of quartz and of metamorphic and granitic rocks are present in subordinate amounts.  Some of the graywacke beds are characterized by a distinctly mottled appearance owing to the presence of laumontite, most commonly in fine-grained tuffaceous-rich layers. Metamorphic detritus becomes increasingly abundant in the upper part of the unit. The graywacke beds display a typical ""Bouma"" sequence grading from massive at the base to laminated in the middle to cross laminated at the top.  Mudstone rip-up clasts are common at the base of the graywacke beds.  The unit has a high graywacke to mudstone ratio and is interpreted to represent middle and outer submarine fan deposits","Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles","","CA003","250","Candle","Sedimentary","2180","Kvg","",""
    "Kgm","Volcanic graywacke and mudstone","Cretaceous","Fine- to coarse-grained, poorly sorted graywacke interbedded with mudstone","Ammonites and pelecypods of Albian age","","BT002","125","Bettles","Sedimentary","2180","Kvg","",""
    "Kgm","Graywacke and mudstone","late Early Cretaceous (Albian)","Fine- to medium-grained, locally calcareous, poorly sorted graywacke interbedded with mudstone","Marine mollusks; Grantziceras and Cleoniceras","","HU002","145","Hughes","Sedimentary","2180","Kvgm","",""
    "Kv","Volcanic graywacke and mudstone","late Early Cretaceous (Albian)","Poorly sorted dark greenish-gray volcanic graywacke and mudstone.","","","SH002","17","Shungnak","Sedimentary","2180","Kvgm","",""
    "Kvg","Graywacke sandstone and mudstone","Early(?) Cretaceous","Chiefly dark-greenish gray to pale-olive tuffaceous and feldspathic fine-to-very coarse-grained sandstone.  Subordinate dark-gray mudstone.  Many sandstone beds distinctly mottled due to partial zeolitization of volcanic material.","Association and gradational(?) with units containing Buchia of earliest Cretaceous age.","","KT004","204","Kateel River","Sedimentary","2180","Kvg","",""
    "Knm","Undifferentiated sedimentary rocks","Cretaceous","Undifferientiated units Km and Kn.  Units on east side of quadrangle reassigned to unit Kvg (NSA 2180).","","","KT002","212","Kateel River","Sedimentary","2180","Kvg","",""
    "Kvg","Volcaniclastic graywacke and mudstone turbidite deposits","Early Cretaceous","Volcaniclastic graywacke and mudstone turbidite deposits","","","NR002","307","Norton Bay","Sedimentary","2180","Kvg","",""
    "Kg","Turbidite deposits","Early Cretaceous","Graywacke and mudstone turbidite deposits.  Polygons in extreme northwest of quadrangle of this unit reassigned to unit Kgw on Wilson and others (1998), lumped back by W.W. Patton, Jr., (1999)","","","NL004","2115","Nulato","Sedimentary","2180","","",""
    "Kcv","Calcareous graywacke and mudstone","Cretaceous","Mixed sequence of calcareous graywacke, calcareous mudstone, volcanic graywacke, and volcanic conglomerate.  Transitional between Kvg and Kcg.  Small area of unit in northeast part of quadrangle reassigned and lumped with unit Kvm by W.W. Patton, Jr. (1999).  Consists of volcanic conglomerate and breccia.","abundant carbonized plant debris","","CA002","230","Candle","Sedimentary","2180","Kvg","",""
    "Kg","Volcaniclastic graywacke and mudstone turbidites","Early Cretaceous","Sub-division of volcaniclastic graywacke and mudstone turbidite deposits (Patton, written commun., 1999).  Dark-gray to green, hard, fine-grained to conglomeratic volcanic graywacke and dark-gray, finely laminated mudstone.  Turbidite assemblage consisting of submarine-fan deposits, chiefly midfan channel, interchannel, and related overbank facies","","","UL002","103","Unalakleet","Sedimentary","2180","","",""
    "Kvg","Volcanic-clast graywacke and mudstone submarine fan deposits.","Cretaceous","Hard, fine-grained to conglomeratic, locally tuffaceous, graywacke and dark-gray finely laminated mudstone. The graywacke is composed of matrix-supported clasts of intermediate and mafic volcanic and intrusive rocks and chert.  Clasts of quartz and of metamorphic and granitic rocks are present in subordinate amounts.  Some of the graywacke beds are characterized by a distinctly mottled appearance owing to the presence of laumontite, most commonly in fine-grained tuffaceous-rich layers. Metamorphic detritus becomes increasingly abundant in the upper part of the unit. The graywacke beds display a typical ""Bouma"" sequence grading from massive at the base to laminated in the middle to cross laminated at the top.  Mudstone rip-up clasts are common at the base of the graywacke beds.  The unit has a high graywacke to mudstone ratio and is interpreted to represent middle and outer submarine fan deposits","Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles","","WI003","114","Wiseman","Sedimentary","2180","","",""
    "Kvg","Volcanic-clast graywacke and mudstone sumbmarine fan deposits","Cretaceous","Volcanic-clast graywacke and mudstone submarine fan deposits","","","RB009","823","Ruby","Sedimentary","2180","Kvg","",""
    "Kgm","Volcanic graywacke and mudstone","Cretaceous","Fine- to coarse-grained, poorly sorted graywacke interbedded with mudstone","Ammonites and pelecypods of Albian age","","WI004","125","Wiseman","Sedimentary","2180","Kvg","",""
    "Kvg","Volcanic-clast graywacke and mudstone ","Cretaceous","Hard, fine-grained to conglomeratic, locally tuffaceous, graywacke and dark-gray finely laminated mudstone. The graywacke is composed of matrix-supported clasts of intermediate and mafic volcanic and intrusive rocks and chert.  Clasts of quartz and of metamorphic and granitic rocks are present in subordinate amounts.  Some of the graywacke beds are characterized by a distinctly mottled appearance owing to the presence of laumontite, most commonly in fine-grained tuffaceous-rich layers. Metamorphic detritus becomes increasingly abundant in the upper part of the unit. The graywacke beds display a typical ""Bouma"" sequence grading from massive at the base to laminated in the middle to cross laminated at the top.  Mudstone rip-up clasts are common at the base of the graywacke beds.  The unit has a high graywacke to mudstone ratio and is interpreted to represent middle and outer submarine fan deposits.","Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles. ","","HU003","2330","Hughes","Sedimentary","2180","","",""
    "Kvg","Volcanic-clast graywacke and mudstone","Cretaceous","Hard, fine-grained to conglomeratic, locally tuffaceous, graywacke and dark-gray finely laminated mudstone. The graywacke is composed of matrix-supported clasts of intermediate and mafic volcanic and intrusive rocks and chert.  Clasts of quartz and of metamorphic and granitic rocks are present in subordinate amounts.  Some of the graywacke beds are characterized by a distinctly mottled appearance owing to the presence of laumontite, most commonly in fine-grained tuffaceous-rich layers. Metamorphic detritus becomes increasingly abundant in the upper part of the unit. The graywacke beds display a typical ""Bouma"" sequence grading from massive at the base to laminated in the middle to cross laminated at the top.  Mudstone rip-up clasts are common at the base of the graywacke beds.  The unit has a high graywacke to mudstone ratio and is interpreted to represent middle and outer submarine fan deposits.","Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles. ","","KT004","204","Kateel River ","Sedimentary","2180","","",""
    "Kvg","Volcanic-clast graywacke and mudstone ","Cretaceous","Hard, fine-grained to conglomeratic, locally tuffaceous, graywacke and dark-gray finely laminated mudstone. The graywacke is composed of matrix-supported clasts of intermediate and mafic volcanic and intrusive rocks and chert.  Clasts of quartz and of metamorphic and granitic rocks are present in subordinate amounts.  Some of the graywacke beds are characterized by a distinctly mottled appearance owing to the presence of laumontite, most commonly in fine-grained tuffaceous-rich layers. Metamorphic detritus becomes increasingly abundant in the upper part of the unit. The graywacke beds display a typical ""Bouma"" sequence grading from massive at the base to laminated in the middle to cross laminated at the top.  Mudstone rip-up clasts are common at the base of the graywacke beds.  The unit has a high graywacke to mudstone ratio and is interpreted to represent middle and outer submarine fan deposits.","Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles. 
","","TN008","32105","Tanana","Sedimentary","2180","","",""
    "Kvg","Volcanic graywacke and conglomerate","Late Cretaceous","Volcanic graywacke and conglomerate","","","OP002","510","Ophir","Sedimentary","2181","Kvm","",""
    "Kcvs/Kcs","Coarse-grained volcaniclastic sandstone and conglomerate","earliest Cretaceous","Greenish gray, poorly sorted fine- to coarse-grained lithic-volcaniclastic sandstone and pebble conglomerate composed chiefly of volcanic rock and chert detritus, and quartz.","Inoceramus","","MD003","2180","Medfra","Sedimentary","2181","lKvg","",""
    "Kcvs/Kcs","Coarse-grained volcaniclastic sandstone and conglomerate","earliest Cretaceous","Greenish gray, poorly sorted fine- to coarse-grained lithic-volcaniclastic sandstone and pebble conglomerate composed chiefly of volcanic rock and chert detritus, and quartz.","Inoceramus","","OP003","2180","Ophir","Sedimentary","2181","Kvm","",""
    "Kvg","Volcanic graywacke and conglomerate","earliest Cretaceous","Poorly sorted fine- to coarse-grained graywacke, sandstone, grit, and pebble to cobble conglomerate composed chiefly of volcanic rock and chert detritus; interbedded dark mudstone.","Inoceramus","","MD002","304","Medfra","Sedimentary","2182","lKvg","",""
    "Kvg","Volcanic graywacke and conglomerate","Late Cretaceous","Hard, fine-grained to conglomeratic, locally tuffaceous, graywacke and dark-gray finely laminated mudstone. The graywacke is composed of matrix-supported clasts of intermediate and mafic volcanic and intrusive rocks and chert.  Clasts of quartz and of metamorphic and granitic rocks are present in subordinate amounts.  Some of the graywacke beds are characterized by a distinctly mottled appearance owing to the presence of laumontite, most commonly in fine-grained tuffaceous-rich layers. Metamorphic detritus becomes increasingly abundant in the upper part of the unit. The graywacke beds display a typical ""Bouma"" sequence grading from massive at the base to laminated in the middle to cross laminated at the top.  Mudstone rip-up clasts are common at the base of the graywacke beds.  The unit has a high graywacke to mudstone ratio and is interpreted to represent middle and outer submarine fan deposits","Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles","","OP005","510","Ophir","Sedimentary","2182","Kvm","",""
    "Kgc","Volcanic graywacke and conglomerate ","Early Cretaceous?","Poorly sorted fine- to coarse-grained graywacke sandstone, grit, and pebble to cobble conglomerate composed chiefly of volcanic rock and chert detritus. Interbedded dark mudstone. Unit is tentatively assigned an Early Cretaceous age.","It locally contains abundant shell prisms thought to have been derived from large- shelled Early Cretaceous species of Inoceramus. ","","MD004","304","Medfra","Sedimentary","2182","","",""
    "Kgc","Volcanic graywacke and conglomerate ","Early Cretaceous?","Poorly sorted fine- to coarse-grained graywacke sandstone, grit, and pebble to cobble conglomerate composed chiefly of volcanic rock and chert detritus. Interbedded dark mudstone. Unit is tentatively assigned an Early Cretaceous age.","It locally contains abundant shell prisms thought to have been derived from large- shelled Early Cretaceous species of Inoceramus. ","","MD004","304","Medfra","Sedimentary","2182","","HFS",""
    "Kfv","Felsic volcanic rocks","middle Cretaceous","Varies locally, consists of latite, quartz latite, and trachyte flows, crystal-lithic tuff, rhyolitic and rhyodacitc welded tuff and flow(?) and hypabyssal intrusive rocks.","","Biotite from tuff yielded 85.2 Ma K-Ar age (not recalculated with new constants)","SH002","25","Shungnak","Igneous","2210","Kve","",""
    "Kac","None","Late Cretaceous","Agglomerate, chert, tuff, and sandstone","","","OP002","506","Ophir","Igneous","2260","Kvl","",""
    "Ktg","Tuff, volcanic graywacke, and mudstone","Early Cretaceous ","Volcaniclastic rocks of andesitic and dacitic composition.  Crystal-lithic tuff, lithic tuff, volcanic graywacke and mudstone.  Rare andesite flows.  Mapped only along northern edge of this quad and in adjoining HU quad.  Overlies Kv and may grad laterally into Kgm","","","MZ002","360","Melozitna","Igneous","2320","Ktg","",""
    "Ktg","Tuff, volcanic graywacke, and mudstone","Late(?) and Early Cretaceous","Andesitic and latitic volcaniclastic rocks including crystal -lithic tuff, lithic tuff, volcanic graywacke, and mudstone","","","HU002","140","Hughes","Sedimentary","2320","","",""
    "Ktg","Tuff, volcanic graywacke, and mudstone ","Early Cretaceous","Chiefly crystal and lithic tuffs and volcanic graywacke interbedded with laminated mudstone. Tuffs and graywacke characterized by abundant potassium feldspar crystals and potassium-rich volcanic rocks fragments.  Unit contains rare mafic and intermediate lava flows. Unit conformably overlies and is transitional into unit Kv.","Unit contains dinoflagellates of late Early Cretaceous (Hauterivian,  Barremian, and possibly Aptian) age.","","HU003","2330","Hughes ","Sedimentary","2320","","",""
    "Kv","Andesitic volcanic rocks","Earliest Cretaceous (Neocomian) but may include Albian age strata","Koyukuk River- Pillow basalt and andesitic flows; andesitic tuffs, volcanic conglomerate, and breccia; chert and fine-grained cherty tuff; coquinoidal limestone composed largely of Buchia sp. Widely altered to a hard dark green hornfels.  Dulbi-Melozitna Rivers- Andesitic and dacitic tuff, breccia, volcanic conglomerate and tuffaceous graywacke.  Flows and hyabyssal bodies of andesite and dacite porphyry.  Dark-green hornfels near Kg.","Buchia sublaevis, belemnite; Buchia cf.B. crassicollis; Buchia keyserlingi","","MZ002","380","Melozitna","Igneous","2330","Kve","",""
    "KJv","Andesitic volcanic rocks","Cretaceous and Jurassic(?)","Chiefly porphyritic pyroxene andesite and trachyandesite flows, andesitic crystal and lithic tuff, and massive andesite breccia, agglomerate, and conglomerate.  Commonly altered and therefore pale green.  Interbedded dark-greenish-gray tuffaceous graywacke, chert, shale, and impure limestone containing Buchia.  Mildly deformed and unaltered vesicular basalt and associated pyroclastic rocks along Koyukuk River near Roundabout Mt. may be of Tertiary age.","Buchia subokensis of earliest Cretaceous age in interbedded sedimentary rocks.","","KT002","800","Kateel River","Igneous","2330","Kv","",""
    "Kv","Andesitic volcanic rocks","Early Cretaceous","Andesite and basalt flows, volcaniclastic rocks, and soubordinate rhyolite and dacite flows.","","","NL003","2220","Nulato","Igneous","2330","","",""
    "Kv","Andesitic volcaniclastic rocks","Early Cretaceous","Dark-greenish-gray crystal and lithic tuff, fine cherty tuff, tuff breccia, and volcanic sandstone and conglomerate.  Koyukuk terrane","Buchia sublaevis Keyserling (Valanginian age), brachiopods, radiolarians (Valanginian age)","","UL002","106","Unalakleet","Sedimentary","2330","","",""
    "Kv","Andesitic volcanic rocks","earliest Cretaceous (Neocomian) but may include Albian age strata","Koyukuk River- Pillow basalt and andesitic flows; andesitic tuffs, volcanic conglomerate, and breccia; chert and fine-grained cherty tuff; coquinoidal limestone composed largely of Buchia sp. Widely altered to a hard dark green hornfels.  Dulbi-Melozitna Rivers- Andesitic and dacitic tuff, breccia, volcanic conglomerate and tuffaceous graywacke.  Flows and hyabyssal bodies of andesite and dacite porphyry.  Dark-green hornfels near Kg.","Buchia sublaevis, belemnite; Buchia cf.B. crassicollis; Buchia keyserlingi","","RB004","2330","Ruby","Igneous","2330","Kve","",""
    "KJv","Andesitic volcanic rocks","Jurassic (?) and Cretaceous","Wide variety of andesite volcanic flows and volcaniclastic crystal and lithic tuffs.  Mainly andesitic and trachyandesitic crystal and lithic tuffs, tuffaceous volcanic graywacke, masssive andesitic breccia, agglomerate, and conglomerate","Simbirskites ammonite of Early Cretaceous","K/Ar age of 120 +/- 3 m.y.","CA002","800","Candle","Igneous","2330","Kv","",""
    "KJv","Andesitic volcanic rocks","Late Jurassic and Early Cretaceous","Volcanic rocks including andesitic crystal-bearing tuff, tuff brecia, and agglomerate intercalated with porphyritic pyroxene andesite and trachyandesite flows","Buchia sublaevis (Keyserling) and B. crassicollis (Keyserling) both of Neocomian age","K/Ar og 134 +/- 5 m.y. of volcanic rocks","HU002","155","Hughes","Sedimentary","2330","","",""
    "Kab","Porphyritic andesite and basalt","Early Cretaceous","Chiefly greenish-gray and dark-reddish porhyritic andesite and basalt flows and shallow intrusive rocks.  Pillows and columnar jointing common.","","K-Ar age of 125 Ma on andesite porphyry and 122 Ma on latite plug.","SH002","27","Shungnak","Igneous","2330","Kve","",""
    "KJv","Andesitic volcanic rocks","earliest(?) Cretaceous and Jurassic(?)","Chiefly dark greenish-gray, andesitic crystal-bearing lithic tuff, volcanic breccia, and volcanic conglomerate with subordinate intercalated trachy andesite and basalt flows.  Minor volcanic graywacke and mudstone.","Abundant Buchia sublevis of earliest Cretaceous locally.","Quartz latite porphyry yielded K-Ar age of 117 Ma on hornblende","SH002","31","Shungnak","Igneous","2330","Kve","",""
    "KJv","Andesitic volcanic rocks","earliest(?) Cretaceous and Jurassic(?)","Chiefly andesitic crystal-bearing lithic tuff, volcanic breccia, and volcanic conglomerate with subordinate intercalated andesitic flows.","Abundant Buchia sublevis of earliest Cretaceous locally.","","SE002","800","Selawik","Igneous","2330","Kve","",""
    "Kv","Andesitic volcanic rocks","Early Cretaceous","Andesitic volcanic rocks","","","NR002","441","Norton Bay","Igneous","2330","lKv","",""
    "Kv","Andesite and basalt flows and volcaniclastic rocks","Early Cretaceous","Andesite and basalt flows and volcaniclastic rocks","","","RB009","828","Ruby","Igneous","2330","lKv","",""
    "KJv?","Andesitic volcanic rocks","earliest(?) Cretaceous and Jurassic(?)","Chiefly dark greenish-gray, andesitic crystal-bearing lithic tuff, volcanic breccia, and volcanic conglomerate with subordinate intercalated trachy andesite and basalt flows.  Minor volcanic graywacke and mudstone.","Abundant Buchia sublevis of earliest Cretaceous locally.","Quartz latite porphyry yielded K-Ar age of 117 Ma on hornblende","SH002","32","Shungnak","Igneous","2330","Kve","Q",""
    "Kab?","Porphyritic andesite and basalt","Early Cretaceous","Chiefly greenish-gray and dark-reddish porhyritic andesite and basalt flows and shallow intrusive rocks.  Pillows and columnar jointing common.","","K-Ar age of 125 Ma on andesite porphyry and 122 Ma on latite plug.","SH002","28","Shungnak","Igneous","2330","Kve","Q",""
    "Kv","Andesite and basalt lava flows and volcaniclastic rocks ","Early Cretaceous","Flows of andesite and basalt, interbedded with tuff, tuff breccia, agglomerate, volcanic conglomerate, and volcanic graywacke.   Flows typically  have phenocrysts of  plagioclase and pyroxene set in a matrix of devitrified glass, altered plagioclase microlites, pyroxene, chlorite, and opaque oxides. Rhyolite and dacite flows are present locally.  Tuffs are composed chiefly of  fine-grained basalt and andesite clasts, plagioclase crystals, and mafic minerals in an altered matrix of devitrified glass. In upper part of the unit, the tuffs are highly calcareous and contain abundant shelly debris, including species of Buchia.  Tuffs commonly occur in cyclically repeated sequences that grade upward from coarse tuff breccia and lapilli tuff to very fine-grained cherty tuff  and blue-green radiolarian chert.  Massive agglomerate, breccia and volcanic conglomerate are present locally. ","Unit contains abundant marine mollusks of early Early Cretaceous (Berriasian and Valanginian) age."," K/Ar isotopic cooling ages range from 137 to 120 M.","OP005","511","Ophir ","Igneous","2330","","",""
    "Kv","Andesite and basalt lava flows and volcaniclastic rocks","Early Cretaceous","Flows of andesite and basalt, interbedded with tuff, tuff breccia, agglomerate, volcanic conglomerate, and volcanic graywacke.   Flows typically  have phenocrysts of  plagioclase and pyroxene set in a matrix of devitrified glass, altered plagioclase microlites, pyroxene, chlorite, and opaque oxides. Rhyolite and dacite flows are present locally.  Tuffs are composed chiefly of  fine-grained basalt and andesite clasts, plagioclase crystals, and mafic minerals in an altered matrix of devitrified glass. In upper part of the unit, the tuffs are highly calcareous and contain abundant shelly debris, including species of Buchia.  Tuffs commonly occur in cyclically repeated sequences that grade upward from coarse tuff breccia and lapilli tuff to very fine-grained cherty tuff  and blue-green radiolarian chert.  Massive agglomerate, breccia and volcanic conglomerate are present locally. ","Unit contains abundant marine mollusks of early Early Cretaceous (Berriasian and Valanginian) age. ","K/Ar isotopic cooling ages range from 137 to 120 Ma. ","KT004","801","Kateel River ","Igneous","2330","","",""
    "Kv","Andesite and basalt lava flows and volcaniclastic rocks","Early Cretaceous","Flows of andesite and basalt, interbedded with tuff, tuff breccia, agglomerate, volcanic conglomerate, and volcanic graywacke.   Flows typically  have phenocrysts of  plagioclase and pyroxene set in a matrix of devitrified glass, altered plagioclase microlites, pyroxene, chlorite, and opaque oxides. Rhyolite and dacite flows are present locally.  Tuffs are composed chiefly of  fine-grained basalt and andesite clasts, plagioclase crystals, and mafic minerals in an altered matrix of devitrified glass. In upper part of the unit, the tuffs are highly calcareous and contain abundant shelly debris, including species of Buchia.  Tuffs commonly occur in cyclically repeated sequences that grade upward from coarse tuff breccia and lapilli tuff to very fine-grained cherty tuff  and blue-green radiolarian chert.  Massive agglomerate, breccia and volcanic conglomerate are present locally. ","Unit contains abundant marine mollusks of early Early Cretaceous (Berriasian and Valanginian) age. ","K/Ar isotopic cooling ages range from 137 to 120 Ma. ","KT004","801","Kateel River ","Igneous","2330","","Q",""
    "Kv","Andesite and basalt lava flows and volcaniclastic rocks","Early Cretaceous","Flows of andesite and basalt, interbedded with tuff, tuff breccia, agglomerate, volcanic conglomerate, and volcanic graywacke.   Flows typically  have phenocrysts of  plagioclase and pyroxene set in a matrix of devitrified glass, altered plagioclase microlites, pyroxene, chlorite, and opaque oxides. Rhyolite and dacite flows are present locally.  Tuffs are composed chiefly of  fine-grained basalt and andesite clasts, plagioclase crystals, and mafic minerals in an altered matrix of devitrified glass. In upper part of the unit, the tuffs are highly calcareous and contain abundant shelly debris, including species of Buchia.  Tuffs commonly occur in cyclically repeated sequences that grade upward from coarse tuff breccia and lapilli tuff to very fine-grained cherty tuff  and blue-green radiolarian chert.  Massive agglomerate, breccia and volcanic conglomerate are present locally","n upper part of the unit, the tuffs are highly calcareous and contain abundant shelly debris, including species of Buchia","","NL004","440","Nulato","Igneous","2330","","",""
    "Kbd","Spilitic pillow basalt and diabase","Early Cretaceous(?)","Dark greenish- to reddish-brown, fine-grained, spilitic amygdaloidal pillow basalt flows and dark-greenish-gray, medium- to coarse-grained, spilitic diabase intrusive rocks.","","","SH002","29","Shungnak","Igneous","2335","Kbd","",""
    "Kbd","Spilitic pillow basalt and diabase","Early Cretaceous(?)","Dark greenish- to reddish-brown, fine-grained, spilitic amygdaloidal pillow basalt flows and dark-greenish-gray, medium- to coarse-grained, spilitic diabase intrusive rocks.  Unit added  in northwest corner by Patton (2000).","","","KT004","2335","Kateel River","Igneous","2335","Kbd","",""
    "Kft","Shoshonitic flows and tuffs","Early Cretaceous","Dark-gray to green lithic tuffs, pillowed flows, diabase, and volcanic conglomerate of shoshonitic composition.  Koyukuk terrane","","K/Ar age of 117+3.5 Ma and 118+3.5 Ma from biotite","UL002","125","Unalakleet","Igneous","2336","","",""
    "Kg","Granitic rocks","Cretaceous","Granitic rocks of acidic and intermediate composition  Chiefly syenite at Roundabout Mountain and albite granite on Huslia River-Derby Creek divide.","","","KT002","600","Kateel River","Igneous","2410","Kg","",""
    "Kg","Granitic rocks, undivided","Cretaceous?","Ray Mountains pluton and part of another large pluton at north central edge of quadrangle.  Quartz monzonite, granite, monzonite, and possibly granodiorite.","","","TN003","2470","Tanana","Igneous","2410","Kg","",""
    "Kag","Albite granite","Cretaceous (?)","Leucocratic medium- to coarse-grained albite granite composed predominately of albite and quartz","","","HU002","190","Hughes","Igneous","2410","","",""
    "Kg","Granodiorite","Late Cretaceous","Fine- to medium-grained  hornblende-biotite granodiorite with subordinate quartz monzonite and quartz diorite.  (Recoded NSA 2420 March, 1999, per Bill Patton.)","","K-Ar date of 82.3 and 89.0 m.y. from the Dulbatna Mountain pluton and 81.5 m.y. from the Indian Mountain pluton in adjoining Hughes quad","MZ002","300","Melozitna","Igneous","2420","Kgd","",""
    "Kg3","Granodiorite and quartz monzonite","Late Cretaceous","Chiefly leucocratic, medium-grained, hornblende-biotite granodiorite and quartz monzonite in Zane Hills and Wheeler Creek plutons","","K-Ar ages of 80.6 and 81.9 Ma","SH002","39","Shungnak","Igneous","2420","Kgd","",""
    "Kgq","Granodiorite and quartz monzonite","Late Cretaceous","Medium-grained hornblende-biotite granodiorite and quartz monzonite with lesser diorite","","K/Ar age of 82 +/- 3 m.y.","HU002","185","Hughes","Igneous","2420","Kgd","",""
    "Kgd","Granodiorite and granite ","Late Cretaceous","Generally fine- to medium-grained equigranular, but locally porphyritic, hornblende-biotite granodiorite, and alaskitic biotite granite.   Locally includes tonalite and quartz monzodiorite.","","K/Ar isotopic cooling ages range from 89 to 78 Ma.","HU003","2420","Hughes ","Igneous","2420","","",""
    "Km","Mafic rocks","Cretaceous?","Gabbro, diorite?  Not on published OFR98-133","","","TN002","2440","Tanana","Igneous","2440","Kgbm","",""
    "Ka3","Alaskite","Late Cretaceous","Medium-grained alaskite at west end of Wheeler Creek plutons","","","SH002","41","Shungnak","Igneous","2450","Kg","",""

    "TKg","Granitic rocks","Cretaceous or Tertiary","Granitic rocks of uncertain composition, texture, and age; may be equivalent to KG unit of Melozitna quadrangle (MZ002)","","","TN003","2480","Tanana","Igneous","2460","Kg","",""
    "Kg","Granodiorite","Late Cretaceous?","Two small plutons in the se part of quadrangle.  Fine- to medium-grained  hornblende-biotite granodiorite with subordinate quartz monzonite and quartz diorite.  Distinguished from others to the north by Bill Patton (March, 1999)  ERROR -- not on map, should be deleted from data base.","","K-Ar date of 82.3 and 89.0 m.y. from the Dulbatna Mountain pluton and 81.5 m.y. from the Indian Mountain pluton in adjoining Hughes quad","MZ002","300","Melozitna","Igneous","2460","Kg","",""
    "TKg","Granite","Cretaceous-Tertiary","Medium- to coarse-grained equigranular to porphyritic biotite granite","","K-Ar age on biotite 65.5 +/- 3.3 Ma","RB005","111","Ruby","Igneous","2460","Kg","",""
    "Kcm","Granitic rocks of Christmas Mountain pluton","Late Cretaceous","Granitic rocks of Christmas Mountain pluton","","","NR002","115","Norton Bay","Igneous","2460","uKgs","",""
    "Kg","Granitic rocks","Late Cretaceous","Quartz monzonite, granite, monzonite, and possibly granodiorite","","K-Ar(?) 92, and 90 Ma; 104 Ma","TN002","2470","Tanana","Igneous","2470","Kg","",""
    "Kg","Granitic rocks","Early Cretaceous ","Granitic rocks of coarsely porphyritic biotite quartz monzonite.  Sub divided by source BT003 into NSA 2530 and 2545","","K/Ar age of 106 +/- 3.0 m.y.","BT002","130","Bettles","Igneous","2470","Kg","",""
    "Ksp","Serpentinite and mafic rocks","Late Cretaceous?","Serpentinite, diabase-gabbro and some metadiorite.  Not on published OFR98-133","","","TN002","2510","Tanana","Igneous","2510","Kum","",""
    "lKgg","Nepheline syenite","Early Cretaceous","Nepheline syenite","","","RB009","827","Ruby","Igneous","2515","lKgg","",""
    "Km
","Quartz Monzonite","Early Cretaceous","Pinkish coarse-grained porphyritic biotite quartz monzonite.  Becomes gnessic in southern part of the Melozitna pluton.  Altered and slightly cataclastic in small pluton east of Gold Mountain.","","K-Ar date 111 m.y. from Melozitna pluton","MZ002","370","Melozitna","Igneous","2530","Kqm","",""
    "Kgr","Granite","Early Cretaceous","Khotol pluton, a large, poorly exposed granite 12 by 20 km in size.  Granite is typically coarsely porphyritic having large K-spar phenocrysts in a moderately coarse groundmass.","","K-Ar age of 112 +/- 3.4 Ma on biotite","NL003","2410","Nulato","Igneous","2530","","",""
    "Kg","Granitic rocks, undivided","Cretaceous?","Part of Melozitna pluton.  Quartz monzonite, granite, monzonite, and possibly granodiorite.","","","TN003","2471","Tanana","Igneous","2530","Kg","",""
    "Kgq","Granodiorite and quartz monzonite","Early Cretaceous","Medium-grained hornblende-biotite granodiorite and quartz monzonite with lesser diorite  (Single small pluton in middle of quadrangle (per Bill Patton, March, 1999)","",".","HU002","185","Hughes","Igneous","2530","Kg","",""
    "Kq2","Quartz monzonite","Early Cretaceous","Chiefly leucocratic, medium-grained porphyritic, biotite quartz monzonite in Purcell Mtn. and Ekiek Creek plutons","","K-Ar age of 98.6 Ma for Purcell Mtns. pluton","SH002","43","Shungnak","Igneous","2530","Kg","",""
    "Kqi+","Quartz monzonite and alaskite","Early Cretaceous","Chiefly leucocratic, fine- to medium-grained cataclastic-textured, monzonite and alaskite","","K-Ar age of 99 Ma","SE002","2530","Selawik","Igneous","2530","Kg","",""
    "Kg","Granitic rocks","probably Late Cretaceous and Early Cretaceous","Chiefly quartz monzonite in Kokrines Hills","","K-Ar date of 111 Ma in Melozitna quad.","RB004","2410","Ruby","Igneous","2530","Kg","",""
    "Kgr","Granite-granodiorite","Early Cretaceous","Consists chiefly of biotite and muscovite-biotite granite and granodiorite.","","K/Ar isotopic cooling  ages range from 112 to 96 Ma and two U/Pb zircon analyses give crystallization ages of 112 and 109 Ma","BT003","131","Bettles","Igneous","2530","Kg","",""
    "Kgr","Granitic rocks","Cretaceous","Granitic rocks of hornblende and pyroxene monzonite and syenite.  Minor biotite quartz monzonite.  Unit subdivided by Patton (1999, 2000)","","lead-alpha age of 90 +/- 10 m.y. and 100 +/- 15 m.y.  K/Ar age of 102 +/- 5 m.y. and K/Ar age of 100 +/- 5 m.y.","CA003","700","Candle","Igneous","2530","Kg","",""
    "Kgr","Quartz monzonite and alaskite","Early Cretaceous","Chiefly leucocratic, fine- to medium-grained cataclastic-textured, monzonite and alaskite","","K-Ar age of 99 Ma","SE004","750","Selawik","Igneous","2530","Kg","",""
    "Kgr","Granite and granodiorite ","Early Cretaceous","Consists chiefly of biotite and muscovite-biotite granite and granodiorite.","","K/Ar isotopic cooling  ages range from 112 to 96 Ma and two U/Pb zircon analyses give crystallization ages of 112 and 109 Ma. ","MZ004","4370","Melozitna","Igneous","2530","","",""
    "Kgr","Granite and granodiorite","Early Cretaceous","Consists chiefly of biotite and muscovite-biotite granite and granodiorite.","","K/Ar isotopic cooling  ages range from 112 to 96 Ma and two U/Pb zircon analyses give crystallization ages of 112 and 109 Ma. ","TN008","32515","Tanana","Igneous","2530","","",""
    "Kn2","Nepheline syenite","Early Cretaceous","Chiefly leucocratic, medium-grained nephelene syenite and related mafic alkaline rocks","","K-Ar age of 107 Ma from Selawik quadrangle","SH002","47","Shungnak","Igneous","2535","Kns","",""
    "Kns","Nepheline syenite","Early Cretaceous","Chiefly leuco- to melanocratic, medium-grained nephelene syenite and malignite, with subordinate ijolite, shonkinite, and pyroxenite.","","K-Ar age of 107 Ma","SE002","2535","Selawik","Igneous","2535","Kns","",""
    "Knsy","Granitic rocks","Cretaceous","Granitic rocks of hornblende and pyroxene monzonite and syenite.  Minor biotite quartz monzonite.  Unit subdivided by Patton (1999, 2000)","","lead-alpha age of 90 +/- 10 m.y. and 100 +/- 15 m.y.  K/Ar age of 102 +/- 5 m.y. and K/Ar age of 100 +/- 5 m.y.","CA003","701","Candle","Igneous","2535","Kns","",""
    "Ksy","Granitic rocks","Cretaceous","Granitic rocks of hornblende and pyroxene monzonite and syenite.  Minor biotite quartz monzonite.  Unit subdivided by Patton (1999, 2000)","","lead-alpha age of 90 +/- 10 m.y. and 100 +/- 15 m.y.  K/Ar age of 102 +/- 5 m.y. and K/Ar age of 100 +/- 5 m.y.","CA003","702","Candle","Igneous","2545","Ksy","",""
    "Km2","Monzonite","Early Cretaceous","Chiefly leucocratic, medium-grained porphyritic, biotite-pyroxene monzonite","","K-Ar age of 99.4 Ma","SH002","45","Shungnak","Igneous","2545","Kg","",""
    "Ks2","Syenite","Early Cretaceous","Chiefly leucocratic, medium-grained gniessic hornblende syenite","","K-Ar age of 100 Ma from Selawik quadrangle","SH002","49","Shungnak","Igneous","2545","Ksy","",""
    "Kgi","Syenite and monzonite","Early Cretaceous","Chiefly leuco- to mesocratic, medium-grained gniessic syenite and monzonite","","K-Ar age of 100 Ma","SE002","700","Selawik","Igneous","2545","Ksy","",""
    "Ksy","Syenite-monzonite","Early Cretaceous","Composed of syenite, monzonite, and subordinate quartz monzonite, monzodiorite, quartz syenite, and nepheline syenite and related mafic alkaline rocks including malignite, ijolite, shonkinite, and pyroxenite","","K/Ar isotopic cooling ages from units Ksy and Knsy range from 113 to 99 Ma","BT003","134","Bettles","Igneous","2545","Ksy","",""
    "Ksy","Granitic rocks","Cretaceous","Granitic rocks of hornblende and pyroxene monzonite and syenite.  Minor biotite quartz monzonite.  Unit subdivided by Patton (1999, 2000)","","lead-alpha age of 90 +/- 10 m.y. and 100 +/- 15 m.y.  K/Ar age of 102 +/- 5 m.y. and K/Ar age of 100 +/- 5 m.y.","CA003","703","Candle","Igneous","2545","Ktt","",""
    "Ksy","Syenite-monzonite","Early Cretaceous","Composed of syenite, monzonite, and subordinate quartz monzonite, monzodiorite, quartz syenite, and nepheline syenite and related mafic alkaline rocks including malignite, ijolite, shonkinite, and pyroxenite","","K/Ar isotopic cooling ages from units Ksy and Knsy range from 113 to 99 Ma","WI003","117","Wiseman","Igneous","2545","","",""
    "KJwc","Wilber Creek and Wolverine quartzite units, undivided","Cretaceous and Jurassic","Wilber Creek and Wolverine quartzite units, undivided (TN003 modified, shown as southern TrPs)","","","TN003","2812","Tanana","Sedimentary","2812","KJwc","",""
    "KJw","Wolverine quartzite unit of Weber and others (1992), undivided","Early Cretaceous and or Jurassic","Light-gray quartzite and dark-gray, cleaved, subphyllitic argillite and shale, part of unit KJcs of Chapman and others.","","","TN003","2815","Tanana","Sedimentary","2815","KJw","",""
    "KJwq","Wolverine quartzite unit of Weber and others (1992), quartzite","Early Cretaceous and or Jurassic","Light-gray  to tan, white weathering, massive-bedded, moderately well-sorted, subrounded fine- to medium-grained quartzarenite.  Correlative with Keenan Quartzite of Charley River quadrangle according to Dover but I wonder if this is the wrong unit and it should be the Wilber Creek quartzite correlated.  (Not on published OFR98-133)","","","TN003","2816","Tanana","Sedimentary","2816","KJwq","",""
    "KJwa","Wolverine quartzite unit of Weber and others (1992), sandstone and shale","Early Cretaceous and or Jurassic","Dominantly gray to black argillaceous rocks containing interbeds of Wolverine-type quartz-arenite.","","","TN003","2817","Tanana","Sedimentary","2817","KJwa","",""
    "Jt","Trondhjemite and tonalite","Late and Middle Jurassic","Trondhjemite, tonalite, and subordinate quartz diorite, diorite, and gabbro forming a long pluton from Unalakleet River valley into the Holy Cross quad.  Koyukuk terrane","","5 K/Ar ages of 154+6 Ma from trondhjemite biotite, 166+7 Ma, 173+9 Ma from tonalite biotite and hornblende, and 148+4.4 Ma and 130+3.9 Ma from tonalite hornblende","UL002","101","Unalakleet","Igneous","3380","","",""
    "pc","Cumulate ultramafic rocks of Mount Hurst","Unknown","Cumulate ultramafic rocks of Mount Hurst: relations uncertain","","","OP002","402","Ophir","Igneous","3496","Jtu","",""
    "Jcu","Cumulate ultramafic rocks","Middle and Late Jurassic","Predominately dunite but also includes wehrlite and olivine clinopyroxenite.  Two exposures of massive chromotote as much as 1.5 m thick noted in dunite.","","","NL003","402","Nulato","Igneous","3496","","",""
    "ph","Harzburgite tectonite of Mount Hurst","Unknown","Harzburgite tectonite of Mount Hurst; relations uncertain","","","OP002","401","Ophir","Igneous","3497","Jtu","",""
    "Jht","Harzburgite tectonite","Middle and Late Jurassic","Harzburgite composed of 20-30 percent orthopyroxenite and as much as 75 percent olivine and minor clinopyroxene and spinel.","","","NL003","401","Nulato","Igneous","3497","","",""
    "JPu","Ultramafics","Permian to Jurassic","Small bodies of serpentinized peridotite and dunite with closely associated gabbro and anorthosite.","","","MZ002","410","Melozitna","Igneous","3498","JPu","",""
    "Ju","Ultramafic rocks","Late Jurassic","Ultramafic rocks","","","OP002","301","Ophir","Igneous","3498","Jtu","",""
    "Juu","Ultramafic rocks, undivided","Middle and Late Jurassic","Partly serpentinized peridotite and dunite intruded by narrow dikes of fresh clinopyroxenite, horblendite, gabbro, and gabbro pegmatite.","","","NL003","301","Nulato","Igneous","3498","","",""
    "Ju","Ultramafic-mafic complexes","Late and Middle Jurassic","Chiefly dark greenish-black serpentinite and serpentinized pyroxenite, peridotite, and dunite with locallized subordinate gabbro.  Koyukuk terrane","","","UL002","102","Unalakleet","Igneous","3498","","",""
    "JPu","Ultramafic rocks","Jurassic (?), Triassic (?), and Permian","Ultramafic rocks of serpentinized peridotite and dunite","","","BT002","145","Bettles","Igneous","3498","Jaum","",""
    "Jdr","Dishna River mafic and ultramafic rocks","Jurassic","Dishna River mafic and ultramafic rocks extension into Ophir quadrangle","","","OP002","600","Ophir","Igneous","3498","Jtu","",""
    "Jumc","Mafic-ultramafic complexes","Jurassic","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite.","","","BT003","118","Bettles","Igneous","3498","Jaum","",""
    "Jumc","Mafic-ultramafic complexes","Jurassic","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite.  Koyukuk Terrane","","K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /39Ar determination from the metamorphic sole yielded a plateau age of 161 Ma","AR003","706","Ambler River","Igneous","3498","MzZum","",""
    "Jumc","Mafic-ultramafic complexes","Jurassic","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite. ","","K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /39Ar determination from the metamorphic sole yielded a plateau age of 161 Ma.","WI003","118","Wiseman","Igneous","3498","","",""
    "MzPzum","Mafic-ultramific complexes","Mesozoic and Paleozoic?","Complexes consist of 3 suites, 1., a cumulate magmatic suite of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2., amantle suite of harzburgite, dunite, and minor clinopyroxenite, and 3., a metamorphic sole of a highly tectonized layer of amphibolite, granet amphibolite, and pyroxene granulite.","","","RB009","820","Ruby","Igneous","3498","Jumc","",""
    "MzPzum","Mafic-ultramfic complexes ","Mesozoic and Paleozoic?","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite. ","","K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /39Ar determination from the metamorphic sole yielded a plateau age of 161 Ma.","OP005","911","Ophir ","Igneous","3498","","",""
    "MzPzum","Mafic-ultramfic complexes ","Mesozoic and Paleozoic?","The complexes consist of: 1) acumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite.","","K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /39Ar determination from the metamorphic sole yielded a plateau age of 161 Ma.","TN008","35190","Tanana","Igneous","3498","","",""
    "MzPzum","Mafic-ultramfic complexes","Mesozoic and Paleozoic?","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite","","K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /39Ar determination from the metamorphic sole yielded a plateau age of 161 Ma","NL004","502","Nulato","Igneous","3498","","",""
    "JTrt","Cherty tuff, crystal and lithic tuff, and volcanic breccia","Triassic and possible early Jurassic","Dark-greenish, very fine grained cherty tuff grading into greenish-gray radiolarian chert.  Fine to coarse-grained dark greenish-gray crystal and lithic tuff.  Volcanic breccia and conglomerate composed of poorly sorted clasts of mafic volcanic rocks and cherty tuff in a crystal and lithic tuff matrix.","Radiolaria and conodonts","","MD002","401","Medfra","Igneous","3851","JTrta","",""
    "JTrt; JTrma","Siliceous tuff, crystal and lithic tuffs, and metasiltstone and Mafic volcanic breccia, tuff, siltstone, chert, and agglomerate","Triassic and early Jurassic","Dark-greenish, very fine grained cherty tuff grading into greenish-gray radiolarian chert.  Fine to coarse-grained dark greenish-gray crystal and lithic tuff.  Volcanic breccia and conglomerate composed of poorly sorted clasts of mafic volcanic rocks and cherty tuff in a crystal and lithic tuff matrix.","Radiolaria and conodonts reported by Patton and others, 1980 (MD002)","","MD003","3851","Medfra","Igneous","3851","JTrta","",""
    "JTrt; JTrma","Siliceous tuff, crystal and lithic tuffs, and metasiltstone and Mafic volcanic breccia, tuff, siltstone, chert, and agglomerate","Triassic and early Jurassic","Dark-greenish, very fine grained cherty tuff grading into greenish-gray radiolarian chert.  Fine to coarse-grained dark greenish-gray crystal and lithic tuff.  Volcanic breccia and conglomerate composed of poorly sorted clasts of mafic volcanic rocks and cherty tuff in a crystal and lithic tuff matrix.","Radiolaria and conodonts reported by Patton and others, 1980 (MD002)","","OP005","3851","Ophir","Igneous","3851","JTrta","",""
    "JMc","Chert, argillite, and volcaniclastic rocks","Triassic, Permian, Pennsylvanian, and Mississippian","Chiefly banded radiolarian chert  interbedded with argillite, cherty  tuff, fine- to coarse-grained crystal and lithic tuff, and volcanic breccia and conglomerate.  Breccia and conglomerate are composed of poorly sorted clasts of mafic volcanic rocks and cherty tuff in a matrix of crystal and lithic tuff.  Unit also includes several small bodies of slightly recrystallized limestone and a few small intrusive bodies of gabbro and diabase","Abundant radiolaria ranging in age from Mississippian to possibly as young as Jurassic","","OP005","5602","Ophir","Sedimentary","3851","TrMc","",""
    "JMc","Cherty tuffs, chert, argillite, graywacke, crystal-lithic tuffs, volcanic breccia, and conglomerate","Jurassic","Cherty tuffs, chert, argillite, graywacke, crystal-lithic tuffs, volcanic breccia, and conglomerate","","","RB009","819","Ruby","Sedimentary","3851","JMc","",""
    "JMc","Chert, cherty tuff, argillite, crystal-lithic tuff, volcanic breccia, and conglomerate ","Jurassic? to Mississippian","Chiefly banded radiolarian chert  interbedded with argillite, cherty  tuff, fine- to coarse-grained crystal and lithic tuff, and volcanic breccia and conglomerate.  Breccia and conglomerate are composed of poorly sorted clasts of mafic volcanic rocks and cherty tuff in a matrix of crystal and lithic tuff.  Unit also includes several small bodies of slightly recrystallized limestone and a few small intrusive bodies of gabbro and diabase. ","Unit contains abundant radiolaria ranging in age from Mississippian to possibly as young as Jurassic.","","MD004","4401","Medfra","Sedimentary","3851","","",""
    "JMc","Chert, cherty tuff, argillite, crystal-lithic tuff, volcanic breccia, and conglomerate","Jurassic? to Mississippian","Chiefly banded radiolarian chert  interbedded with argillite, cherty  tuff, fine- to coarse-grained crystal and lithic tuff, and volcanic breccia and conglomerate.  Breccia and conglomerate are composed of poorly sorted clasts of mafic volcanic rocks and cherty tuff in a matrix of crystal and lithic tuff.  Unit also includes several small bodies of slightly recrystallized limestone and a few small intrusive bodies of gabbro and diabase.  Unit contains abundant radiolaria ranging in age from Mississippian to possibly as young as Jurassic
Replacement of polygons coded 99 from OP002","","","OP005","5902","Ophir","Sedimentary","3851","bu","",""
    "Trs","Spiculite and sandy limestone","Late Triassic (Norian)","Dark-gray banded spiculite and chert, yellowish-orange-weathering sandy fossiliferous limestone and conglomerate and dark-gray shale","Monotis ochotica, M. of M. scutiformis, Halobia, Heterastridium","","MD002","402","Medfra","Sedimentary","4032","Trsl","",""
    "Trc","Carbonatite","Triassic","Magnetite-rich carbonatite.","","","TN005","3495","Tanana","Igneous","4340","Trc","",""
    "Jsc","Serpentinite and or carbonatite","Jurassic?","Carbonatite of unit Jsc","","","TN003","3495","Tanana","Igneous","4340","Trc","",""
    "Ps","Slaty shale, siltstone, graywacke, and conglomerate","Permian","Moderately well-indurated, medium- to dark-gray shale, commonly weakly foliated to slaty, and in part phyllitic.  Well indurated, medium- to medium-drak-gray siltstone, in part argillite.","","","TN002","5740","Tanana","Sedimentary","5012","TrPs","",""
    "TrPs","Sedimentary rocks, undivided","Permian to Triassic","Dominantly dark-gray, typically phyllitic, silicieous to carbonaceous argillite and shale, having subordinate but characteristic clast-supported chert-rich conglomerate, greenish-gray chert, tuffaceous volcaniclastic rocks, yellowish- to reddish-brown highly calcareous argillite or limestone, and minor mafic intrusive rocks.  May include older (Devonian? or Mississippian?) or younger (Cretaceous) rocks locally.","","","TN003","5740","Tanana","Sedimentary","5012","Ps","",""
    "JMr","Rampart Group and associated mafic intrusive rocks, undivided","Mississippian to Jurassic","Rampart Group volcanic and sedimentary rock sequence","","","TN003","5020","Tanana","Igneous","5020","TrMts","",""
    "m","Marble","Age not given","Blocks of bedded or massive marble of unknown age or affinity in melange of unit MzPzm.  Polygons in unit KJm assigned NSACLASS of 5200","","","BM002","905","Baird Mountains","Metamorphic","5020","TrMts","",""
    "c","Metachert","Age not given","Sinlge block of bedded metachert in melange of  MzPzm.  Other blocks in unit KJm assigned NSACLASS of 5200","","","BM002","902","Baird Mountains","Metamorphic","5020","TrMts","",""
    "TrMs","None","Triassic, Permian, Pennsylvanian, and Mississippian","Sandstone, grit, and argillite","","","OP002","601","Ophir","Sedimentary","5021","TrMis","",""
    "Pg","Graywacke","Permian","Unit probably correlative with similar clastic rocks of the Permian(?) Rampart Group.  Unit has three parts; a) fine- to medium-grained, medium-gray to dark-greenish-gray graywacke, calcareous in part and containing some dark-gray shale fragments, b) grit to small-pebble graywacke conglomerate with clasts of andesitic and basaltic rock, shale, chert, quartzite, and a few schistose rocks in a sand and mud matrix; and c) greenish-gray to medium-dark gray mudstone and shale.","Nodosinellids (Tetrataxis), bryozoan and echinoderm debris.","","RB003","104","Ruby","Sedimentary","5021","TrMis","",""
    "TrMv; TrMcs","Mafic tuff, volcaniclastic sandstone, and minor mafic flows and Calcareous, lithic pebble sandstone","Triassic to Mississippian","Medium- to dark-gray, coarse-grained augite-plagioclase-rich mafic tuff, volcaniclastic sandstone, and porphyritic basaltic andesite and basalt.  Also, light- to medium-green-gray, medium- to coarse-grained, commonly calcareous lithic pebble sandstone and minor medium-gray siltstone containing distinctive pebbles of green-gray chert, argillite, and tuff.","Veghicyclia spp., Pseudoheliodiscus spp., and Sarla spp. of Norian age and Crytostome bryozoan, brachiopod and pelmatozoan fragments of probable late Paleozoic age","","MD003","5021","Medfra","Sedimentary","5021","TrMis","",""
    "TrMv; TrMcs","Mafic tuff, volcaniclastic sandstone, and minor mafic flows and Calcareous, lithic pebble sandstone","Triassic to Mississippian","Medium- to dark-gray, coarse-grained augite-plagioclase-rich mafic tuff, volcaniclastic sandstone, and porphyritic basaltic andesite and basalt.  Also, light- to medium-green-gray, medium- to coarse-grained, commonly calcareous lithic pebble sandstone and minor medium-gray siltstone containing distinctive pebbles of green-gray chert, argillite, and tuff.","Veghicyclia spp., Pseudoheliodiscus spp., and Sarla spp. of Norian age and Crytostome bryozoan, brachiopod and pelmatozoan fragments of probable late Paleozoic age","","OP003","5021","Ophir","Sedimentary","5021","TrMis","",""
    "TrMg","Graywacke, grit, and argillite","Triassic? to Mississippian?","Fine- to medium-grained, commonly calcareous graywacke and granule conglomerate, which contain clasts of chert, shale, argillite, and volcanic rocks.   Graywacke and conglomerate are interbedded with argillite","Unit contains microfossils and bryozoan and echinoids fragments assigned  to a Permian(?)  age in the Ruby quadrangle and assigned more generally to a late Paleozoic age in the Ophir quadrangle.  Unit appears to interfinger locally with unit TrDc","","MD004","4403","Medfra","Sedimentary","5021","","",""
    "TrMg","Graywacke, grit, and argillite","Triassic? to Mississippian?","Fine- to medium-grained, commonly calcareous graywacke and granule conglomerate, which contain clasts of chert, shale, argillite, and volcanic rocks.   Graywacke and conglomerate are interbedded with argillite.  Unit appears to interfinger locally  with unit TrDc","","Unit contains microfossils and bryozoan and echinoids fragments assigned  to a Permian(?) age in the Ruby quadrangle and assigned more generally to a late Paleozoic age in the Ophir quadrangle.","RB009","836","Ruby","Sedimentary","5021","","",""
    "TrMc","Banded chert and argillite","Triassic, Permian, Pennsylvanian, and Mississippian","Medium- to dark-gray, green, and some red radiolarian chert, interbedded dark-gray argillite, and very minor tuffaceous volcanic rocks.  Not on current map","Albaillella sp.(Middle and Late Mississippian), Latentibifistula sp. (Pennsylvanian and Permian), Capnodoce sp. (Triassic?)","","OP003","6080","Ophir","Sedimentary","5112","TrMica","",""
    "Pzmi","Intermediate to mafic intrusive rocks","Paleozoic","Fine- to medium-grained gabbro, subordinate quartz diorite, quartz monzonite, orthopyroxene gabbro, and pyroxenite.  Commonly sill-like.  Wallrocks are restricted to the Rampart Group","","","RB005","114","Ruby","Igneous","5113","JPztm","",""
    "vr","Volcanic rocks","unknown","Chiefly basalt and andesite.  Rarely rhyolite, tuff, chert, agglomerate, and breccia.  Probably of several different ages.  Not shown on map as this unit, rather is NSACLASS 1000 and 2330","","","NL002","601","Nulato","Igneous","5120","MzPzv","",""
    "JMr","Rampart Group and associated mafic intrusive rocks, undivided","Mississippian to Jurassic","Rampart Group volcanic and sedimentary rock sequence, mafic rocks divided out","","","TN003","5133","Tanana","Igneous","5130","JTrtmu","",""
    "JMms","Mafic and sedimentary rocks","Jurassic? to Mississippian","Rampart Group volcanic and sedimentary rock sequence","","","TN002","5131","Tanana","Igneous","5131","TrMru","",""
    "TrMbc","Pillow basalt, chert and minor argillite","Triassic to Mississippian","Altered aphanitic and porphyritic pillow basalt.  Phenocrysts in the porphyritic basalt are composed chiefly of olivine and pyroxene.  Basalt is interlayered with chert and subordinate beds of agglomerate containing clasts of basalt and chert","Chert contains bryozoans and radiolaria of late Paleozoic and possibly Triassic age","","OP005","604","Ophir","Igneous","5131","TrMtsu","",""
    "TrMbc","Pillow basalt, chert and minor argillite","Triassic to Mississippian","Altered aphanitic and porphyritic pillow basalt.  Phenocrysts in the porphyritic basalt are composed chiefly of olivine and pyroxene.  Basalt is interlayered with chert and subordinate beds of agglomerate containing clasts of basalt and chert","Chert contains bryozoans and radiolaria of late Paleozoic and possibly Triassic age","","MD004","604","Medfra","Igneous","5131","TrMtsu","",""
    "TrMbc","Pillow basalt, chert, and minor agglomerate","Triassic? to Mississippian?","Altered aphanitic and porphyritic pillow basalt.  Phenocrysts in the porphyritic basalt are composed chiefly of olivine and pyroxene.  Basalt is interlayered with chert and subordinate beds of agglomerate containing clasts of basalt and chert.","Chert contains bryozoans and radiolari a of late Paleozoic and possibly  Triassic age. ","","MD004","606","Medfra","Igneous","5131","","",""
    "JMr","Rampart Group and associated mafic intrusive rocks, undivided","Mississippian to Jurassic","Rampart Group volcanic and sedimentary rock sequence, mafic rocks divided out","","","TN003","5132","Tanana","Igneous","5132","JMtru","",""

    "mi","Metamorphic igneous rock","Carboniferous (?) Late Paleozoic","Greenstone, locally some gray to red chert, greenstone tuff, and graywacke. Greenstone altered from basalt, diabase, and andesite extrusives and diorite, diabase, gabbro, and pyroxenite intrusives.  In Nulato quad assigned a Carboniferous(?) age.  May include greenstone from older metamorphic complex.","","","RB002","401","Ruby","Metamorphic","5133","JMtu","",""
    "Pzrgs","Rampart Group","Paleozoic","Argillaceous and arenaceous rocks, siliceous and calcareous chemical sedimentary rocks and volcanic rocks.  Pzrgs is of a lower metamorphic grade than Pzrgmsv and consists of gray, green, black, and tan slate and siltstone interbedded with green to gray gray-wacke and lesser white to green chert.","Limestone near Yuki mountain yielded a Devonian fossil age, considered highly suspect","","RB005","112","Ruby","Metamorphic","5133","JMtu","",""
    "Pzrgmsv","Rampart Group","Paleozoic","Argillaceous and arenaceous rocks, siliceous and calcareous chemical sedimentary rocks and volcanic rocks.  Pzrgmsv is of a higher metamorphic grade than Pzrgs and consists of phyllite or fine-grained quartz-muscovite-chlorite schist intercalated with metagraywacke, recrystalized chert, and greenstone.  Three cleavage planes create pencil fracturing","","","RB005","113","Ruby","Metamorphic","5133","JMtu","",""
    "JPb","Basalt and diabase","Permian to Jurassic.","Spilitic basalt and diabase largely altered to greenstone.  Along contact with Km, altered to mafic hornfels.   Probably correlative with similar rocks on strike to the NE in the Tanana and Bettles quads","","","MZ002","400","Melozitna","Igneous","5140","JPb","",""
    "TrMb","Basalt, gabbro, and chert","Triassic, Permian, Pennsylvanian, and Mississippian","Basalt, gabbro, and chert","","","OP002","603","Ophir","Igneous","5140","JMab","",""
    "TrMb","Altered basalt, gabbro, and chert","Mississippian to Triassic","Variably altered and metamorphosed dark-green to gray flows and shallow intrusives of basalt, diabase, and gabbro locally interlayered with volcaniclastic rocks of basaltic composition, bedded chert, and argillaceous rocks","","","NL003","5130","Nulato","Igneous","5140","","",""
    "JPb","Basalt and diabase of Rampart Group","Jurassic to Permian","Basalt and diabase of Rampart Group.","","","RB003","5140","Ruby","Igneous","5140","JMab","",""
    "JMbc","Basalt and chert","Mississippian to Jurassic?","Dominantly basalt, altered basalt, and subordinate diabase and a low-grade cataclastic assemblage of generally dark gray chert and silicieous argillite.  Also subordinate volcaniclastic rocks and minor Mississippian limestone","","","TN003","5140","Tanana","Igneous","5140","JPb","",""
    "JPb","Basalt and diabase","Permian to Jurassic.","Spilitic basalt and diabase largely altered to greenstone.  Along contact with Km, altered to mafic hornfels.   Probabaly correlative with similar rocks on strike to the NE in the Tanana and Bettles quads","","","RB004","5140","Ruby","Igneous","5140","JMab","",""
    "Jv","Altered mafic volcanic rocks","Jurassic","Volcanic rocks including aphanitic amygdaloidal andesite and basalt flows; possibly correlative with rocks of Christian quadrangle (Reiser and others, 1965)","","K/Ar age of 155 to 168 m.y.","HU002","160","Hughes","Igneous","5140","","",""
    "Jv","Mafic volcanic rocks","Jurassic (?)","Chiefly dark-greenish gray basalt flows and diabase intrusives; commonly altered or partially altered to aggregate of chlorite, epidote, and sodic plagioclase","","K-Ar ages of 155 and 168 Ma in the Christian quadrangle.","SH002","35","Shungnak","Igneous","5140","JMab","",""
    "Jv","Altered mafic volcanic rocks","Jurassic (?)","Dark-greenish gray altered basalt and diabase; commonly altered or partially altered to aggregate of chlorite, epidote, and sodic plagioclase","","K-Ar ages of 155 and 168 Ma in the Christian quadrangle.","SE002","160","Selawik","Igneous","5140","JMab","",""
    "b","Metabasalt","Age not given","Metabasaltic rock of unknown age, not as a separate mappable unit(?), but of significant size within other units to warrant distinction on the map.  Polygons associated with unit MzPzm included here.  Other polygons in units DOb and KJm, assigned NSACLASS of 5200","","","BM002","901","Baird Mountains","Metamorphic","5140","JMab","",""
    "JDv","Altered basalt, gabbro, and chert.","Jurassic and Devonian","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.  Angayucham-Tozitna Terrane","","","SP003","704","Survey Pass","Metamorphic","5140","","",""
    "JDv","Altered basalt, gabbro, and chert","Jurassic","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.","","","BT003","119","Bettles","Metamorphic","5140","JMab","",""
    "JDv","Altered basalt, gabbro, and chert","Jurassic and Devonian","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.  Angayucham-Tozitna Terrane","","","AR003","707","Ambler River","Metamorphic","5140","JMab","",""
    "JDv","Altered basalt, gabbro, and chert","Jurassic and Devonian","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.  Angayucham-Tozitna Terrane","","","BM003","1006","Baird Mountains","Metamorphic","5140","JMab","",""
    "JDv","Altered basalt, gabbro, and chert","Jurassic","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.","","","WI003","119","Wiseman","Metamorphic","5140","","",""
    "JDv","Altered basalt, gabbro, chert, interbedded with argillite, tuffs, and graywacke","Jurassic to Devonian","Altered basalt, gabbro, chert, interbedded with argillite, tuffs, and graywacke","","","RB009","818","Ruby","Igneous","5140","JDv","",""
    "JDv","Altered basalt, gabbro, chert, argillaceous rocks, tuff, graywacke, and carbonate rocks","Jurassic to Devonian","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.","Radiolaria from chert  in this unit range in age from Devonian to Jurassic.  Sparse megafossils from the carbonate rocks range in age from Devonian to Permian. The carbonate rocks in the lower part of the unit contain redeposited shallow-water conodont faunas that range in age from Ordovician to Late Mississippian","","SH004","5140","Shungnak","Metamorphic","5140","","",""
    "JDv","Altered basalt, gabbro, chert, argillaceous rocks, tuff, graywacke, and carbonate rocks ","Jurassic to Devonian","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.  In the southeastern part of the Nulato quadrangle and adjoining parts of the Ruby quadrangle, the unit is characterized by sill-like bodies of diabase and gabbro, argillaceous rocks, fine-grained to conglomeritic graywacke, and chert.","Radiolaria from chert  in this unit range in age from Devonian to Jurassic.  Sparse megafossils from the carbonate rocks range in age from Devonian to Permian. The carbonate rocks in the lower part of the unit contain redeposited shallow-water conodont faunas that range in age from Ordovician to Late Mississippian. ","","OP005","603","Ophir ","Metamorphic","5140","","",""
    "JDv","Altered basalt, gabbro, chert, argillaceous rocks, tuff, graywacke, and carbonate rocks","Jurassic to Devonian","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.  In the southeastern part of the Nulato quadrangle and adjoining parts of the Ruby quadrangle, the unit is characterized by sill-like bodies of diabase and gabbro, argillaceous rocks, fine-grained to conglomeritic graywacke, and chert.","Radiolaria from chert  in this unit range in age from Devonian to Jurassic.  Sparse megafossils from the carbonate rocks range in age from Devonian to Permian. The carbonate rocks in the lower part of the unit contain redeposited shallow-water conodont faunas that range in age from Ordovician to Late Mississippian. ","","HU003","160","Hughes ","Metamorphic","5140","","",""
    "JDv","Altered basalt, gabbro, chert, argillaceous rocks, tuff, graywacke, and carbonate rocks ","Jurassic to Devonian","Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabbro are weakly metamorphosed to prehnite-pumpellyite facies and generally increase in metamorphic grade structurally downward.  Greenschist facies metamorphism and locally high-pressure blueschist metamorphism, as indicated by the presence of glaucophane and lawsonite, occur near the base of the terrane where it strucurally overlies the Ruby terrane.  The chert includes both interpillow and bedded varieties and ranges from pure radiolarian and spiculitic chert to cherty tuff.","Radiolaria from chert  in this unit range in age from Devonian to Jurassic.  Sparse megafossils from the carbonate rocks range in age from Devonian to Permian. The carbonate rocks in the lower part of the unit contain redeposited shallow-water conodont faunas that range in age from Ordovician to Late Mississippian. ","","TN008","35140","Tanana","Metamorphic","5140","","",""
    "JPv","Mafic volcanic and intrusive rocks","Jurassic (?), Triassic (?), and Permian","Mafic volcanic and intrusive rocks including pillow basalt, diabase, and gabbro; subordinate basaltic and andesitic volcaniclastic rocks, chert, and cherty mudstone","Foraminifera and brachiopoda of Permian age","","BT002","140","Bettles","Igneous","5145","JMab","",""
    "JDu","Undifferentiated altered volcanic rocks and phyllite","Devonianto Jurassic","Mafic volcanic rocks (Jv) and phyllite (Dp) in complex fault and intrusive relationships.  Unit replaced on published coverage per Patton (Class 205, NSA 5145)","","","HU002","165","Hughes","Tectonite","5145","MzPzl","",""
    "KJm","Melange","Cretaceous and (or) Jurassic","Tectonic melange","Radiolarian chert of Pennsylvanian or Permian age","","BM002","202","Baird Mountains","Sedimentary","5145","Kmk","",""
    "MzPzm","Melange and phyllite","Mesozoic to Paleozoic","Dark gray to black siliceous phyllite with fault-bounded blocks of marble, ribbon chert, dolostone, metabasite, schist, and serpentinite.","","","BM002","404","Baird Mountains","Sedimentary","5145","JMtu","",""
    "c","Metachert","Age not given","Blocks of bedded metachert in melange of unit KJm.  Single polygon in unit MzPzm assigned NSACLASS of 5020.","","","BM002","902","Baird Mountains","Metamorphic","5145","Jsch","",""
    "cs","Chlorite schist","Age not given","Blocks of chlorite schist in melange of MzPzm.","","","BM002","903","Baird Mountains","Metamorphic","5145","Jsch","",""
    "m","Marble","Age not given","Blocks of bedded or massive marble of unknown age or affinity in melange of unit KJm.  Polygons in unit MzPzm assigned NSACLASS of 5020","","","BM002","905","Baird Mountains","Metamorphic","5145","Jsch","",""
    "MzPzl","Melange","Mesozoic and Paleozoic","Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  |ca and |cr  and altered basalt, diabase, and gabbro from unit JDv are mapped separately.
Melange probably formed during time of tectonic emplacement of Angayucham-Tozitna terrane structurally above Arctic Alaska and Ruby terranes.","","","SP003","705","Survey Pass","Tectonite","5145","","",""
    "MzPzl","Melange in a matrix of phyllite","Mesozoic and Paleozoic","Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  |ca and |cr  and altered basalt, diabase, and gabbro from unit JDv are mapped separately.
Melange probably formed during time of tectonic emplacement of Angayucham-Tozitna terrane structurally above Arctic Alaska and Ruby terranes.","","","AR003","708","Ambler River","Tectonite","5145","JMtu","",""
    "MzPzl","Melange in a matrix of phyllite","Mesozoic and Paleozoic","Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  |ca and |cr  and altered basalt, diabase, and gabbro from unit JDv are mapped separately.
Melange probably formed during time of tectonic emplacement of Angayucham-Tozitna terrane structurally above Arctic Alaska and Ruby terranes.","","","BM003","1005","Baird Mountains","Tectonite","5145","MzPzl","",""
    "MzPzl","Melange","Mesozoic and Paleozoic","Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  |ca and |cr  and altered basalt, diabase, and gabbro from unit JDv are mapped separately.
Melange probably formed during time of tectonic emplacement of Angayucham-Tozitna terrane structurally above Arctic Alaska and Ruby terranes.","","","HU003","205","Hughes","Tectonite","5145","MzPzl","",""
    "MzPzl","Melange","Mesozoic and Paleozoic","Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  Pzca and Pzcr  and altered basalt, diabase, and gabbro from unit JDv are mapped separately.
Melange probably formed during time of tectonic emplacement of Angayucham-Tozitna terrane structurally above Arctic Alaska and Ruby terranes.ranes","","","BT003","172","Bettles","Tectonite","5145","MzPzl","",""
    "JPv","Mafic volcanic and intrusive rocks","Jurassic (?), Triassic (?), and Permian","Mafic volcanic and intrusive rocks including pillow basalt, diabase, and gabbro; subordinate basaltic and andesitic volcaniclastic rocks, chert, and cherty mudstone","Foraminifera and brachiopoda of Permian age","","WI004","140","Wiseman","Igneous","5145","JMab","",""
    "KJm","Melange","Early Cretaceous? and Jurassic","Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  |ca and |cr  and altered basalt, diabase, and gabbro from unit JDv are mapped separately.
Melange probably formed during time of tectonic emplacement of Angayucham-Tozitna terrane structurally above Arctic Alaska and Ruby terranes.","","","TN008","35145","Tanana","Tectonite","5145","","",""
    "Jpu","Ultramafic rocks","Jurassic","Serpentinized peridotite and dunite","","","TN002","5150","Tanana","Igneous","5150","Jpu","",""
    "JMu","Mafic and ultramafic rocks, undivided","Jurassic?","Massive and layered gabbro, leucogabbro, harzburgite, garnet amphibolite, serpentinized peridotite, and dunite","","","TN003","5150","Tanana","Igneous","5150","Jpu","",""
    "JPu","Ultramafic rocks","Permian to Jurassic","Small bodies of serpentinized peridotite and dunite with closely associated gabbro and anorthosite.","","","RB004","5150","Ruby","Igneous","5150","Jaum","",""
    "Js","Serpentinite","Jurassic","Numerous small highly sheared and tectonically emplaced(?) bodies of serpentinite, also a large mass of serpentinite at Asbestos Mtn in the Cosmos Hills, and a large mass of partially serpentinized peridotite and dunite in the Jade Mtns.","","","SH002","37","Shungnak","Igneous","5150","Jaum","",""
    "s","Serpentinite","Age not given","Green and black serpentinite of unknown age or source associated with melange of unit MzPzm (Most of unit on map, associated with unit KJm, assigned NSACLASS of 5190)","","","BM002","906","Baird Mountains","Metamorphic","5150","Jaum","",""
    "Jumc","Mafic-ultramfic complexes ","Paleozoic","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite.","","","CA003","802","Candle","Igneous","5150","Jumc","",""
    "MzPzum","Mafic-ultramfic complexes","Mesozoic and Paleozoic?","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite","","","SH004","3350","Shungnak","Igneous","5150","","",""
    "MzPzum","Mafic-ultramfic complexes ","Mesozoic and Paleozoic?","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite. ","","K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /39Ar determination from the metamorphic sole yielded a plateau age of 161 Ma.","CA003","802","Candle ","Igneous","5150","","",""
    "MzPzum","Mafic-ultramfic complexes","Mesozoic and Paleozoic?","The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a highly tectonized layer of amphibolite, garnet amphibolite, and pyroxene granulite.  The harzburgite in the mantle suite typically is partly to mostly serpentinized. Chromite is generally restricted to centimeter-scale layers in dunite and as an accessory mineral. The complexes are intruded by narrow dikes of fresh clinopyroxenite, hornblendite, gabbro, and gabbro pegmatite. ","","K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /39Ar determination from the metamorphic sole yielded a plateau age of 161 Ma.","SH004","3350","Shungnak","Igneous","5150","","",""
    "Jsc","Serpentinite and or carbonatite","Jurassic?","Serpentinite, diabase-gabbro and some metadiorite and magnetite-rich","","","TN003","3495","Tanana","Igneous","5190","MzZum","",""
    "s","Serpentinite","Age not given","Green and black serpentinite of unknown age or source associated with melange of unit KJm  (Single polygon associated with unit MzPzm assigned NSACLASS of 5150","","","BM002","906","Baird Mountains","Metamorphic","5190","MzZum","",""
    "Pzsr","Schistose rocks","middle Paleozoic?","Chiefly white, light- to medium-gray, silvery gray, and brownish gray, fine- to coarse-grained quartz-mica-garnet schist.  Unit apparently conformable with unit Pzl, but contact is poorly exposed.","","","TN002","5208","Tanana","Metamorphic","5208","MzPzrc","",""
    "Pzsr","Schist of Ruby and Garnet Creeks area","Paleozoic?","Polymetamorphic staurolite-garnet-schist containing subordinate quartzite, and hornblende amphibolite","","","TN003","5208","Tanana","Metamorphic","5208","MzPzrc","",""
    "b","Metabasalt","Age not given","Metabasaltic rock of unknown age, not as a separate mappable unit(?), but of significant size within other units to warrant distinction on the map.  In DOb and KJm. Polygons within unit MzPzm assigned NSACLASS of 5140","","","BM002","901","Baird Mountains","Metamorphic","5241","Jsch","",""
    "MzPzma","Metabasite.  Arctic Alaska Terrane","Mesozoic and Paleozoic","Varies from thinly layered greenschist to more massively layered greenstone bodies representing altered mafic and intermediate volcanic and  shallow intrusive rocks. The characteristic minerals are chlorite, albite, actinolite, and epidote.  Unit may include rocks of several different ages.  Some of the bodies are interlayered with the Devonian felsic schist of unit Df and are part of a bimodal volcanic  assemblage.  Other bodies are interlayered with carbonate rocks (unit Pzca) that contain fossils of probable Devonian and Mississippian age.  Still other bodies may represent tectonically emplaced slices of unit JDv of the Angayucham-Tozitna terrane.","","","SP003","701","Survey Pass","Metamorphic","5241","","",""
    "MzPzma","Metabasite","Mesozoic and Paleozoic","Varies from thinly layered greenschist to more massively layered greenstone bodies representing altered mafic and intermediate volcanic and  shallow intrusive rocks. The characteristic minerals are chlorite, albite, actinolite, and epidote.  Unit may include rocks of several different ages.  Some of the bodies are interlayered with the Devonian felsic schist of unit Df and are part of a bimodal volcanic  assemblage.  Other bodies are interlayered with carbonate rocks (unit Pzca) that contain fossils of probable Devonian and Mississippian age.  Still other bodies may represent tectonically emplaced slices of unit JDv of the Angayucham-Tozitna terrane.","","","AR003","709","Ambler River","Metamorphic","5241","MzPzm","",""
    "MzPzma","Metabasite","Mesozoic and Paleozoic","Varies from thinly layered greenschist to more massively layered greenstone bodies representing altered mafic and intermediate volcanic and  shallow intrusive rocks. The characteristic minerals are chlorite, albite, actinolite, and epidote.  Unit may include rocks of several different ages.  Some of the bodies are interlayered with the Devonian felsic schist of unit Df and are part of a bimodal volcanic  assemblage.  Other bodies are interlayered with carbonate rocks (unit Pzca) that contain fossils of probable Devonian and Mississippian age.  Still other bodies may represent tectonically emplaced slices of unit JDv of the Angayucham-Tozitna terrane.","","","BM003","1007","Baird Mountains","Metamorphic","5241","MzPzm","",""
    "MzPzma","Metabasite","Mesozoic/Paleozoic","Varies from thinly layered greenschist to more massively layered greenstone bodies representing altered mafic and intermediate volcanic and  shallow intrusive rocks. The characteristic minerals are chlorite, albite, actinolite, and epidote.  Unit may include rocks of several different ages.  Some of the bodies are interlayered with the Devonian felsic schist of unit Df and are part of a bimodal volcanic  assemblage.  Other bodies are interlayered with carbonate rocks (unit Pzca) that contain fossils of probable Devonian and Mississippian age.  Still other bodies may represent tectonically emplaced slices of unit JDv of the Angayucham-Tozitna terrane.","","","WI003","123","Wiseman","Metamorphic","5241","","",""
    "MzPzma","Metabasite","Mesozoic or Paleozoic","Varies from thinly layered greenschist to more massively layered greenstone bodies representing altered mafic and intermediate volcanic and  shallow intrusive rocks. The characteristic minerals are chlorite, albite, actinolite, and epidote.  Unit may include rocks of several different ages.  Some of the bodies are interlayered with the Devonian felsic schist of unit Df and are part of a bimodal volcanic  assemblage.  Other bodies are interlayered with carbonate rocks (unit Pzca) that contain fossils of probable Devonian and Mississippian age.  Still other bodies may represent tectonically emplaced slices of unit JDv of the Angayucham-Tozitna terrane.","","","HU003","5090","Hughes","Metamorphic","5241","MzPzm","",""
    "MzPzma","Metabasite","Mesozoic or Paleozoic","Varies from thinly layered greenschist to more massively layered greenstone bodies representing altered mafic and intermediate volcanic and  shallow intrusive rocks. The characteristic minerals are chlorite, albite, actinolite, and epidote.  Unit may include rocks of several different ages.  Some of the bodies are interlayered with the Devonian felsic schist of unit Df and are part of a bimodal volcanic  assemblage.  Other bodies are interlayered with carbonate rocks (unit Pzca) that contain fossils of probable Devonian and Mississippian age.  Still other bodies may represent tectonically emplaced slices of unit JDv of the Angayucham-Tozitna terrane.","","","SE004","3008","Selawik","Metamorphic","5241","MzPzm","",""
    "PzZm","Metabasite","Paleozoic and Proterozoic?","Green to dark-greenish-gray, thinly layered greenschist and more massively layered greenstone","","","NL003","8450","Nulato","Metamorphic","5242","","",""
    "MzPzmr","Metabasite","Paleozoic","Massive greenstone to thinly layered greenschist bodies that probably represent metamorphosed mafic to ultramafic intrusive rocks and mafic to intermediate flows and tuffs.  Unit  is intercalated with with units PzZsr, Pzcr, and Dgnr","","","BT003","132","Bettles","Metamorphic","5242","MzPzm","",""
    "MzPzmr","Metabasite","Mesozoic? to Proterozoic?","Massive greenstone to thinly layered greenschist bodies that probably represent metamorphosed mafic to ultramafic intrusive rocks and mafic to intermediate flows and tuffs.  Unit  is intercalated with with units PzZsr, Pzcr, and Dgnr.","","","TN008","35090","Tanana","Metamorphic","5242","","",""
    "Jv","Altered mafic volcanic rocks","Mesozoic or Paleozoic","Dark-greenish gray altered basalt and diabase; commonly altered or partially altered to aggregate of chlorite, epidote, and sodic plagioclase.  Separated from rest of unit; occurs only in southwest part of quadrangle.","","","SE002","3011","Selawik","Metamorphic","5243","MzPzm","",""
    "mi","Metamorphosed igneous rocks","post - Carboniferous","Greenstone, and locally some gray to red chert, dark-gray crystalline limestone, greenstone, tuff, and graywacke.  Greenstone is altered basalt and diabase of probable extrusive origin and diorite, diabase, gabbro, and pyroxenite of probable intrusive origin.  Does not appear on published map, later mapping shows as TrMb (Patton, written commun., 1997)","","","NL002","401","Nulato","Metamorphic","5250","MzPmi","",""
    "MzPzi","Intrusive rocks of intermediate to mafic composition","Mesozoic to Paleozoic","Light- to medium-green, massive, semischistose, fine- to medium-grained, inequigranular, locally porphyroblastic, metadiorite and metagabbro with relict igneous textures.","","","BM002","403","Baird Mountains","Metamorphic","5250","MzPmi","",""
    "MzPzb","Altered basalt and diabase","Mesozoic (?) and Paleozoic (?)","Variably altered and metamorphosed dark-green to gray basalt and diabase.  Angayucham (?) terrane","Similar assemblage of rocks in Holy Cross and  Russian Mission quads have conodont, radiolarian, coral, and molluscan faunas of Carboniferous age.","","UL002","107","Unalakleet","Metamorphic","5280","","",""
    "Pzm","Mafic rocks","Paleozoic?","Metamorphosed mafic igneous rocks, ranging from metagabbro and metadiabase to greenstone, amphibolite, and garnet amphibolite. (Shown on source map compilation as unit Pzg)","","","TN003","5141","Tanana","Metamorphic","5285","Pzrmi","",""
    "MzPzfm","Metabasic and metafelsic volcanic rocks, undifferentiated.","Mesozoic/Paleozoic","Metabasic and metafelsic volcanic rocks, undifferentiated.","","","WI003","125","Wiseman","Metamorphic","5295","Dav","",""
    "Pzd","Dolostone","Paleozoic","Very pale-orange to moderate-reddish-brown, creamy weathering, very fine-grained, slightly calcitic dolostone, locally laminated.","","","BM002","801","Baird Mountains","Sedimentary","5300","","",""
    "Pzbs","Black shale and carbonate rocks","Paleozoic","Dark gray to black siliceous and calcareous shale, with intercalated meter scale lenses of white- to tan-weathering gray limestone or dolostone, and lenses of light green volcaniclastic rocks.","","","BM002","808","Baird Mountains","Sedimentary","5300","","",""
    "DOsl","Shaly limestone","Ordovician to Middle Devonian","Dark-gray to grayish-orange finely laminated limestone and dolomitic limestone.  Suborbinate laminated dolomite, dark chert, and silicous siltstone.  Interpreted as deep-water facies of Osl, Od, and DSl carbonate units.  Now named East Fork Hills Formation (Patton, 2002)","Conodonts","","MD002","508","Medfra","Sedimentary","5310","DCd","",""
    "Pzl","Limestone and schist -- Limestone and dolomite","middle Paleozoic","Chiefly light-gray, massively bedded recrystallized limestone and dolomite, containing subordnate calcareous mica schist and dark phyllite","Tentatively assigned middle Paleozoic age based on correlation with fossiliferous carbonate rocks in the Solomon quadrangle","","CA002","301","Candle","Sedimentary","5320","Pzls","",""
    "Pzc","Carbonate rocks","Early Paleozoic","Carbonate rocks","","","NR002","440","Norton Bay","Sedimentary","5320","Pzc","",""
    "Pzl","Limestone","middle Paleozoic","Light-gray, recrystallized, limestone and dolomite containing minor intercalated phyllite and mica schist. Seward terrane, southwest part of quadrangle","","","SE002","301","Selawik","Metamorphic","5320","Pzld","",""
    "Pzls","Limestone and schist","Paleozoic","Undivided limestone and schist in areas of poor exposure","","","CA002","305","Candle","Sedimentary","5321","Pzls1","",""
    "Pzu","Carbonate rocks and schist","Paleozoic","Undivided carbonate rocks and schist in areas of poor exposure","","","NR002","448","Norton Bay","Metamorphic","5321","PzZu","",""
    "PzZu","Schist and phyllite","middle Paleozoic","Chiefly light- to dark-gray fine-grained quartz-mica schist and grayish-black phyllite.  Subordinate calcareous schist, limestone, chlorite schist, and amphibolite schist.  May locally include metasedimentary rocks of middle Cretaceous age.  Subdivison added by Patton (2000)","","","SE004","3000","Selawik","Metamorphic","5321","Pzpq","",""
    "Pzs","Limestone and schist -- Quartz-mica schist, mica schist, and quartzite","Paleozoic","Quartz-mica schist, mica schist, and quartzite.  Locally includes calcareous, graphitic, and feldspathic schists, amphibolite schist, phyllite, and thin limestone.  Age and stratigraphic relationship with unit Pzl uncertain, contact may be gradational.","","","CA002","300","Candle","Metamorphic","5322","PzZls","",""
    "Pzs","Pelitic schist, calc schist, and quartzite","Paleozoic and Proterozoic?","Quartz-muscovite-graphite schist, calc schist, quartzofeldspathic schist, phyllite, and quartzite.  Unit is locally interlayered with unit Pzcs and is therefore, at least in part, Paleozoic in age.  Some of the unit may be as old as Proterozoic.
","","Samples of the schist yielded a metamorphic mineral K/Ar isotopic cooling age of 124 Ma","NR003","8","Norton Bay","Metamorphic","5322","PzZls","",""
    "Dl","Limestone","Devonian","Dark-gray, partly recrystallized limestone carrying light-colored, crushed crinoid columns, and  associated slate, shale, and fine-grained arkose.  No longer on map, lumped in unit JMtu","light-colored, crushed crinoid columns","","RB002","801","Ruby","Sedimentary","5340","Ds","",""
    "Pzm","Marble","Paleozoic","Small masses of white to light-gray coarsely crystalline dolomitic and calcareous marble.  Locally altered to calc-silicate hornfels","","","MZ002","600","Melozitna","Metamorphic","5340","Pzrm","",""
    "mcl","Metamorphic complex","Precambrian or Paleozoic","Recystallized limestone - superceded, see source NL003","","","NL002","8610","Nulato","Metamorphic","5340","Pzrm","",""
    "MDl","Limestone","Mississippian to Devonian","Limestone","","","OP002","701","Ophir","Sedimentary","5340","MDl","",""
    "Pzc","None","Early Paleozoic","Carbonates","","","OP002","801","Ophir","Sedimentary","5340","Pzrm","",""
    "PaMcl","Limestone and sandstone","Mississippian","Lenticular beds of fossiliferous limestone having subordinate beds of sandy limestone, chert grit, and arkosic sandstone.","Conodonts and foraminifera","","MD002","503","Medfra","Sedimentary","5340","Pzrm","",""
    "Pzc","Carbonate rocks","Early Paleozoic","Gray to white, partly to wholy recrystallized limestone, dark-gray dolomite, and impure schistose limestone.","","","NL003","8610","Nulato","Sedimentary","5340","","",""
    "Pzc","Carbonate rocks","Early Paleozoic","see unit 7520 Od in Ruby or unit 5340, Ophir quadrangle.  Did not appear on final map.","","","RB003","5340","Ruby","Sedimentary","5340","Pzrm","",""
    "Pzl","Metalimestone and marble","Paleozoic?","Metalimestone and marble","","","TN003","5525","Tanana","Metamorphic","5340","Pzrm","",""
    "Ml","Limestone","Mississippian","Gray, bioclastic limestone, found in structurally isolated thrust slice  Not on OFR98-133","","","TN003","6330","Tanana","Sedimentary","5340","DSl","",""
    "Dld","Limestone and dolomite","Latest Devonian (Famennian)","Light- to medium-gray or tan marker units of sandy, platy limestone and massive-bedded silicified limestone and dolostone having extensive locally developed boxwork silica.  Not on OFR98-133","Platy limestone and a limestone bed thought to be part of the section contains sparse conodonts of Famennian age.","","TN003","6905","Tanana","Sedimentary","5340","DSl","",""
    "Dlr","Limestone of Raven Ridge","Late Devonian?","Gray micritic limestone and brecciated limestone.","Undescribed megafossils","","TN003","6931","Tanana","Sedimentary","5340","DSl","",""
    "Pzmr","Marble","Paleozoic?","Distinctive marker bed of coarsely recrystallized marble within Pzsr unit","","","TN003","6955","Tanana","Metamorphic","5340","DSls","",""
    "Pzrm","Ruby Marble","Paleozoic (?)","Medium- to coarse-grained marble composed of calcite with minor musovite, pyrite, and diopside (?).  Probably correlative with Tamarack Bluff limestone","","","RB005","117","Ruby","Metamorphic","5340","Dm","",""
    "Pzm","Marble","Late Paleozoic or Devonian","Small masses of coarsely crystalline marble; local hornfels","","","BT002","150","Bettles","Metamorphic","5340","Pzrm","",""
    "Pzcr","Marble","Late Paleozoic or Devonian","Gray to white, partly to wholly recrystallized limestone, marble, dark-gray dolomitic marble, and impure schistose limestone.  Unit occurs in layers as much as 25m thick intercalated with quartz-mica schist, mica schist, graphitic schist, metabasite, and quartzite.  Some contacts are gradational; others are sharp and may be faulted.","Unit contains conodonts of Middle Ordovician age in the Nulato quadrangle and  poorly preserved corals of Ordovician to Late Mississippian age in the Ruby quadrangle","","BT003","173","Bettles","Metamorphic","5340","Pzrm","",""
    "Pzcr","Carbonate rocks","Paleozoic","Gray to white, partly to wholly recrystallized limestone, marble, dark-gray dolomitic marble, and impure schistose limestone.  Unit occurs in layers as much as 25m thick intercalated with quartz-mica schist, mica schist, graphitic schist, metabasite, and quartzite.  Some contacts are gradational; others are sharp and may be faulted.","Unit contains conodonts of Middle Ordovician age in the Nulato quadrangle and  poorly preserved corals of Ordovician to Late Mississippian age in the Ruby quadrangle","","RB009","832","Ruby","Sedimentary","5340","Pzc","",""
    "Pzcr","Carbonate rocks ","Paleozoic","Gray to white, partly to wholly recrystallized limestone, marble, dark-gray dolomitic marble, and impure schistose limestone.  Unit occurs in layers as much as 25m thick intercalated with quartz-mica schist, mica schist, graphitic schist, metabasite, and quartzite.  Some contacts are gradational; others are sharp and may be faulted.","Unit contains conodonts of Middle Ordovician age in the Nulato quadrangle and  poorly preserved corals of Ordovician to Late Mississippian age in the Ruby quadrangle. ","","OP005","801","Ophir","Sedimentary","5340","","",""
    "Pzcr","Carbonate rocks ","Paleozoic","Gray to white, partly to wholly recrystallized limestone, marble, dark-gray dolomitic marble, and impure schistose limestone.  Unit occurs in layers as much as 25m thick intercalated with quartz-mica schist, mica schist, graphitic schist, metabasite, and quartzite.  Some contacts are gradational; others are sharp and may be faulted.","Unit contains conodonts of Middle Ordovician age in the Nulato quadrangle and  poorly preserved corals of Ordovician to Late Mississippian age in the Ruby quadrangle. ","","TN008","35340","Tanana","Sedimentary","5340","","",""
    "JPzu","Undifferentiated mafic volcanic rocks and phyllite","Jurassic and late Paleozoic and early Mesozoic","Mafic volcanic rocks (unit Jv) and dark phyllite (Pzp), undivided, in complex fault and intrusive relationships","","","SH002","33","Shungnak","Igneous","5410","Pzvs","",""
    "MzPzr","Reindeer Hills complex","Paleozoic","Thermally altered and metasomatized carbonate rocks, schist, and quartzite intruded by numerous small felsic and mafic bodies","","","NR002","394","Norton Bay","Metamorphic","5521","MzPzrc","",""
    "Dl","Limestone","Devonian","Light-gray fine-grained recrystallized limestone; probably correlative with Skajit Limestone of Wiseman (Brosge and Reiser, 1960, 1964)","","","HU002","170","Hughes","Sedimentary","5525","Dm","",""
    "Pzl","Partly recrystallized, reef-like limestone and dolomite","Mississippian or Devonian?","Chiefly light-gray, partly recrystallized, reef-like limestone and dolomite containing minor intercalated phyllite and schist.  Isolated masses resemble Lisburne Group and may be of Mississippian age.","Corals and stromatoporoids of probable Devonian age locally abundant.  ","","SH002","21","Shungnak","Metamorphic","5525","Dm","",""
    "Pzl","Limestone","middle Paleozoic","Light-gray, recrystallized, limestone and dolomite containing minor intercalated phyllite and mica schist.  Arctic Alaska terrane, northern part of quadrangle","","","SE002","301","Selawik","Metamorphic","5525","Dm","",""
    "Pzkm","Marble of Klery Creek","Paleozoic","White-weathering, medium- to light-gray marble having subordinate intercalated gray to green quartz-chlorite schist, black carbonaceous quartzite, and tan calcareous mica schist.","Early Devonian to Late Silurian conodonts and earliest Mississippian conodonts","","SE003","5320","Selawik","Metamorphic","5525","Dm","",""
    "Pzm","Marble","Paleozoic","White to gray, fine to coarsely crystalline, massive to platy marble and subordinate light-gray, finely crystalline dolostone.","","","BM002","802","Baird Mountains","Metamorphic","5525","Dm","",""
    "Pzca","Carbonate rocks","Paleozoic","Ranges from light gray to white partly recrystallized limestone to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovician to Mississippian and may locally include rocks as old as Cambrian. Arctic Alaska terrane","Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area","","SP003","700","Survey Pass","Sedimentary","5525","Dm","",""
    "Pzca","Carbonate rocks","Paleozoic","Ranges from light gray to white partly recrystallized limestone to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovician to Mississippian and may locally include rocks as old as Cambrian. Arctic Alaska terrane","Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area","","AR003","712","Ambler River","Sedimentary","5525","Dm","",""
    "Pzca","Carbonate rocks","Paleozoic","Ranges from light gray to white partly recrystallized limestone to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovician to Mississippian and may locally include rocks as old as Cambrian. Arctic Alaska terrane","Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area","","BM003","5525","Baird Mountains","Sedimentary","5525","Dm","",""
    "Pzca","Carbonate rocks","Paleozoic","Ranges from light gray to white partly recrystallized limestone to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovician to Mississippian and may locally include rocks as old as Cambrian. Arctic Alaska terrane","Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area","","WI003","126","Wiseman","Sedimentary","5525","Dm","",""
    "Pzca","Carbonate rocks","Paleozoic","Ranges from light gray to white partly recrystallized limestone to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovician to Mississippian and may locally include rocks as old as Cambrian. Arctic Alaska terrane","Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area","","SH004","712","Shungnak","Sedimentary","5525","Dm","",""
    "Pzca","Carbonate rocks","Early Paleozoic","Ranges from light gray to white partly recrystallized limestone  to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovician to Mississippian and may  locally include  rocks as old as Cambrian. 
","Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area","","SE004","3003","Selawik","Sedimentary","5525","Pzc","",""
    "Pzm","Marble","Late Paleozoic or Devonian","Small masses of coarsely crystalline marble; local hornfels","","","WI004","150","Wiseman","Metamorphic","5525","Pzrm","",""
    "PzpCq","Quartzite","Paleozoic or Precambrian","Fine-grained, light-gray quartzite and micaceous quartzite with subordinate quartz-mica schist, marble, and calc-silicate rock.  Stratigraphic relationship to PzpCs uncertain.","","","MZ002","710","Melozitna","Metamorphic","5542","PzZrpg","",""
    "TrMq","Quartzite, phyllite, limestone","Mississippian to Triassic","Interbedded white to light-gray banded quartzite, dark phyllite, and gray laminated limestone forming two klippen overlying Ruby terrane rocks in the Kaiyuh Mountains","","","NL003","5542","Nulato","Metamorphic","5542","","",""
    "Pzrp","Ruby Phyllite","Paleozoic (?)","Graphitic phyllite with minor interbedded graphitic quartzite and quartzite.  Locally fine-grained graphitic schist and graphitic quartz-mica schist.  Hornfelsed when adjacent to TKg","","","RB005","115","Ruby","Metamorphic","5542","TrMtqp","",""
    "MzPzq","Quartzite-metachert, carbonate rocks, phyllite","Mesozoic? and Paleozoic?","Quartzite-metachert, carbonate rocks, phyllite","","","NR002","378","Norton Bay","Metamorphic","5542","MzPzq","",""
    "PzpCs","Schistose metamorphic rocks","Early Paleozoic or Late Precambrian","Schistose metamorphic rocks -- Unit on northern edge of map recorrelated based on information from Bill Patton","","","OP002","802","Ophir","Metamorphic","5542","TrMtqp","",""
    "MzPzq","Quartzite-metachert, carbonate rocks, phyllite","Mesozoic? and Paleozoic?","Interbedded white to light-gray banded quartzite, dark phyllite, and gray laminated limestone. Thin sections show the quartzite to be composed of as much as 99 percent interlocking quartz grains.  Thin layers of white mica folia give the quartzite a faint foliation. The white and light-gray banding, the purity of the quartzites, and the even texture of the quartz grains suggest that the quartzite is a recrystallized chert (metachert). The quartzite is locally interlayered with dark-gray, finely laminated, slightly foliated siliceous argillite, dark phyllite, and a talcy chloritic schist","In the Nulato quadrangle the limestone is partly recrystallyzed and silicified and locally contains unidentifiable coral and crinoid fragments.  In the Melozitna quadrangle, thin marble beds contain conodonts and crinoids of Devonian age","","CA003","801","Candle","Metamorphic","5542","MzPzq","",""
    "PzpCq","Quartzite","Paleozoic or Precambrian","Fine-grained, light-gray quartzite and micaceous quartzite with subordinate quartz-mica schist, marble, and calc-silicate rock.  Stratigraphic relationship to PzpCs uncertain.","In the Nulato quadrangle the limestone is partly recrystallyzed and silicified and locally contains unidentifiable coral and crinoid fragments.  In the Melozitna quadrangle, thin marble beds contain conodonts and crinoids of Devonian age","","MZ004","4710","Melozitna","Metamorphic","5542","PzZrpg","",""
    "MzPzq","Quartzite-metachert, carbonate rocks, phyllite","Paleozoic to Mesozoic","Quartzite-metachert, carbonate rocks, phyllite","","","RB009","826","Ruby","Metamorphic","5542","MzPzq","",""
    "MzPzq","Quartzite (metachert), carbonate rocks, and phyllite","Mesozoic? and Paleozoic","Interbedded white to light-gray banded quartzite, dark phyllite, and gray laminated limestone. Thin sections show the quartzite to be composed of as much as 99 percent interlocking quartz grains.  Thin layers of white mica folia give the quartzite a faint foliation. The white and light-gray banding, the purity of the quartzites, and the even texture of the quartz grains suggest that the quartzite is a recrystallized chert (metachert). The quartzite is locally interlayered with dark-gray, finely laminated, slightly foliated siliceous argillite, dark phyllite, and a talcy chloritic schist.  In the central Ruby quadrangle, the unit is composed chiefly of  phyllite and fine-grained quartz-muscovite-chlorite schist interbedded with metagraywacke, recrystallized chert, greenstone, and rare marble. ","In the Nulato quadrangle the limestone is partly recrystallyzed and silicified and locally contains unidentifiable coral and crinoid fragments.  In the Melozitna quadrangle, thin marble beds contain conodonts and crinoids of Devonian age (Harris, written commun., 1983).  Some of the metachert may be as young as Mesozoic and correlative with  the Mesozoic chert in unit JDv.     ","","TN008","35542","Tanana","Metamorphic","5542","","",""
    "Dp","Phyllite","Devonian (?)","Locally calcareous and chloritic phyllite; age based on correlation with similar rocks in Wiseman and Chandalar quads (Brosge and Reiser, 1964).  Unit subdivided by Patton.","","","HU002","175","Hughes","Metamorphic","5560","Pzp","",""
    "Pzpa","Phyllite","Triassic to Mississippian","Metagraywacke and phyllite with chert interlayers and metagabbro dikes.  Unit MzPzs of Dillon and others (1986) subdivided by Patton (2000, written communication) into Pzg, graywacke and Pzp, Phyllite and subordinate metagraywacke.","","","WI003","120","Wiseman","Metamorphic","5560","Pzp","",""
    "Pzpa","Phyllite.  ","Paleozoic","Dark phyllite and minor metagraywacke that have a penetrative fabric ranging from slaty cleavage to weakly schistose.  Unit locally contains slices of little deformed shallow-water Devonian carbonate rocks that are enveloped in basalt flows and debris-flow(?) breccias composed of blocks of vesicular basalt in a matrix of volcanic and carbonate debris.  Arctic Alaska Terrane","","","SP003","779","Survey Pass","Metamorphic","5560","","",""
    "Pzpa","Phyllite","Paleozoic","Dark phyllite and minor metagraywacke that have a penetrative fabric ranging from slaty cleavage to weakly schistose.  Unit locally contains slices of little deformed shallow-water Devonian carbonate rocks that are enveloped in basalt flows and debris-flow(?) breccias composed of blocks of vesicular basalt in a matrix of volcanic and carbonate debris.  Arctic Alaska Terrane","","","AR003","713","Ambler River","Metamorphic","5560","Pzp","",""
    "Pzpa","Phyllite","Paleozoic","Dark phyllite and minor metagraywacke that have a penetrative fabric ranging from slaty cleavage to weakly schistose.  Unit locally contains slices of little deformed shallow-water Devonian carbonate rocks that are enveloped in basalt flows and debris-flow(?) breccias composed of blocks of vesicular basalt in a matrix of volcanic and carbonate debris.","","","HU003","210","Hughes","Metamorphic","5560","Pzp","",""
    "Pzp","Phyllite","Late Paleozoic or Devonian","Dark-gray to black phyllite with subordinate fine-grained metagraywacke","","","WI004","155","Wiseman","Metamorphic","5560","Pzp","",""
    "Pzpa","Phyllite and subordinate metagraywacke","Paleozoic(?)","Dark phyllite and minor metagraywacke that have a penetrative fabric ranging from slaty cleavage to weakly schistose.  Unit locally contains slices of little deformed shallow-water Devonian carbonate rocks that are enveloped in basalt flows and debris-flow(?) breccias composed of blocks of vesicular basalt in a matrix of volcanic and carbonate debris.  Age of unit is probably middle or late Paleozoic.  Correlative with |pr unit in the Ruby terrane","Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area","","BM003","5560","Baird Mountains","Sedimentary","5560","Dm","",""
    "Pzp","Phyllite","Late Paleozoic or Devonian","Dark-gray to black phyllite with subordinate fine-grained metagraywacke","","","BT002","155","Bettles","Metamorphic","5561","Pzp","",""
    "PzPr","Phyllite ","Paleozoic?","Phyllite and subordinate fine-grained metagraywacke cut by abundant vein quartz. The phyllite and metagraywacke are overprinted by a low-grade penetrative metamorphic fabric, but turbidite features, such as sole marks and graded bedding, are locally discernible.  Age of unit is uncertain,  probably Devonian or late Paleozoic.  Correlative with unit Pzpa in the Arctic Alaska terrane","","","TN008","35560","Tanana","Metamorphic","5561","","",""
    "Pzg","Graywacke","Late Paleozoic or Devonian","Dark-greenish-gray fine-grained impure graywacke.  In Wiseman quad.","","","WI004","","Wiseman","Sedimentary","5565","Pzg","",""
    "Pzg","Metagraywacke","Triassic to Mississippian","Metagraywacke and phyllite with chert interlayers and metagabbro dikes.  Unit MzPzs of Dillon and others (1986) subdivided by Patton (2000, written communication) into Pzg, Metagraywacke and subordinate phyllite and Pzpa, phyllite.","","","WI003","121","Wiseman","Metamorphic","5565","Pzg","",""
    "Pzg","Metagraywacke","Paleozoic","Fine- to medium-grained metagraywacke and metasiltstone  composed chiefly of quartz and chert clasts, but in places containing a significant component of volcanic rock and feldspar clasts.  Overprinted by low-grade penetrative metamorphic fabric, but turbidite features, such as graded bedding and sole marks, are locally discernible.  Interbedded with subordinate amounts of phyllite","","","SP003","709","Survey Pass","Metamorphic","5565","","",""
    "Pzg","Graywacke","Paleozoic","Fine- to medium-grained metagraywacke and metasiltstone  composed chiefly of quartz and chert clasts, but in places containing a significant component of volcanic rock and feldspar clasts.  Overprinted by low-grade penetrative metamorphic fabric, but turbidite features, such as graded bedding and sole marks, are locally discernible.  Interbedded with subordinate amounts of phyllite","","","HU003","205","Hughes","Metamorphic","5565","Pzg","",""
    "Pzg","Metagraywacke and subordinate phyllite ","Paleozoic?","Fine- to medium-grained metagraywacke and metasiltstone composed chiefly of quartz and chert clasts, but in places containing a significant component of volcanic rock and feldspar clasts.  Overprinted by low-grade penetrative metamorphic fabric, but turbidite features, such as graded bedding and sole marks, are locally discernible.  Interbedded with subordinate amounts of phyllite.","","","HU003","205","Hughes ","Metamorphic","5565","","",""
    "Pzar","Argillaceous rocks","Permian or Middle to Late Devonian","Thin-bedded siltstone, slate, and phyllite, thick-bedded argillite, and minor laminated sandstone.  Metamorphosed to low grade.  Not on published OFR98-133","","","TN002","5615","Tanana","Sedimentary","5615","PDms","",""
    "Ps","Sandstone, sandy limestone, and conglomerate","Permian","Fine- to coarse-grained yellowish-orange-weathering sandstone, limy sandstone, siltstone, and conglomerate.","Kuvelousia, Spiriferella, Waagenoconcha","","MD002","501","Medfra","Sedimentary","5740","Ps","",""
    "Ps","Sandstone, sandy limestone and conglomerate","Permian","Sandstone, sandy limestone and conglomerate","","","RB009","834","Ruby","Sedimentary","5740","Ps","",""
    "Pg","Graywacke, conglomerate and mudstone","Permian","Fine- to medium-grained graywacke, graywacke conglomerate with basalt, andesite, shale, chert, quartzite, and schist clasts, and green to gray mudstone.  Possibly correlative to graywacke of Rampart Group.","microfossils of probable Permian age","","RB003","121","Ruby","Sedimentary","5745","Pig","",""
    "Pg","Graywacke, conglomerate, and mudstone","Permian","Fine- to medium-grained graywacke, graywacke conglomerate with basalt, andesite, shale, chert, quartzite, and schist clasts, and green to gray mudstone.","Contains microfossils of probable Permian age","","RB005","121","Ruby","Sedimentary","5745","","",""
    "Kc","Chert and argillite","Cretaceous","Chert and argillite with interbedded rhyolitic tuff, sandstone, and grit.","Fragmentary fossil imprint identified as small immature ammonite of Cretaceous or Jurassic type.","","RB002","303","Ruby","Sedimentary","6080","Pig","",""
    "TrDc","Chert, argillite, and volcaniclastic rocks","Triassic? to Devonian","Varicolored radiolarian chert, lenticular beds of fossiliferous limestone and interbedded argillite.  Subordinate beds of sandy limestone, grit, and arkosic sandstone.","Unit contains abundant radiolaria, condonts, and foraminifera that range in age from latest Devonian to possibly as young as Triassic","","OP005","602","Ophir","Sedimentary","6080","TrMc","",""
    "PaMc","Chert and limestone","Pennsylvanian and Mississippian","Chiefly greenish-gray, dark-gray to black, and red radiolarian chert.","Radiolarians","","MD002","502","Medfra","Sedimentary","6080","TrMica","",""
    "MDc","Chert and argillite","Late(?) Mississippian and very latest Devonian","Medium-dark to dark-gray, thin-banded, bedded, radiolarian-bearing chert containing thin interbeds of slaty argillite.  (See unit 6080 in MD quadrangle, correlated in part.).  Mapped as Kca by Cass (1959)","Radiolarians","","RB003","303","Ruby","Sedimentary","6080","TrMica","",""
    "MDc","Chert and Slate","Mississippian and Devonian","Thin-banded grey, green, and red chert with thin interbeds of slate","Chert contains radiolarians of Devonian, Mississippian(?), and Mississippian age","","RB005","122","Ruby","Metamorphic","6080","TrMica","",""
    "TrMc","Banded chert and argillite","Pennsylvanian and Mississippian","Medium- to dark-gray, green, and some red radiolarian chert. interbedded dark-gray argillite, and very minor tuffaceous volcanic rocks","Radiolarians","","MD003","6080","Medfra","Sedimentary","6080","TrMica","",""
    "TrMc","Chert and limestone","Triassic","Chert and limestone","","","RB009","824","Ruby","Metamorphic","6080","TrMc","",""
    "TrDc","Chert, argillite, and limestone ","Triassic? to Devonian","Varicolored radiolarian chert, lenticular beds of fossiliferous limestone and interbedded argillite.  Subordinate beds of sandy limestone, grit, and arkosic sandstone.","Unit contains abundant radiolaria, condonts, and foraminifera that range in age from latest Devonian to possibly as young as Triassic.
","","MD004","502","Medfra","Sedimentary","6080","","",""
    "Dao","Augen orthogneiss","Devonian","Augen most commonly of white potassium feldspar, range in size from 1 to 10 cm long, most about 4 cm long.  Biotite is scarce to abundant.  Foliation layers containing biotite bend around augen.","","","TN003","6520","Tanana","Metamorphic","6522","MDrao","",""
    "Km
","Augen orthogniess","Early Cretaceous","Gnessic phase in southern part of the Melozitna pluton now recognized as augen orthogneiss.  ","","","MZ003","3370","Melozitna","Metamorphic","6522","MDrao","",""
    "Dgnr","Granitic gneiss","Devonian","Strongly foliated quartzofeldspathic gneiss.  Consists of a coarse- to medium-grained porphyroclastic biotite-quartz-feldsparmuscovite mylonite gneiss containing resistant augen of K-feldspar in a ductile matrix of mica, quartz, and feldspar. ","","A U/Pb zircon determination from unit in the Tanana quadrangle yielded  a crystallization  age of 390 Ma, which suggests that it is approximately the same age as unit Dgna in the Arctic Alaska terrane.","TN008","36522","Tanana","Metamorphic","6522","","",""
    "Kg1","Granite","Early Cretaceous","Chiefly leucocratic, medium-grained gniessic muscovite-biotite albite granite in Cosmos Hills","","K-Ar age of 100 Ma from Selawik quadrangle","SH002","51","Shungnak","Igneous","6523","MDaao","",""
    "Dgna","Gneissic granite","Devonian","Foliated gneissic granite composed of albite, potassium feldspar, quartz, muscovite, and biotite.  Intruded by aplite dikes.","","Pluton yielded a probable Devonian U/Pb zircon crystallization age.  Correlative in age with unit Dgnr in the Ruby terrane.","SH004","711","Shungnak","Metamorphic","6523","MDaao","",""
    "Mq","Globe quartzite","Mississippian","Vitreous quartzite associated with gabbro sills and dikes.  Light-gray quartzite.  Massive or thinly interbedded quartzite and medium- to dark-gray slate, phyllite, and minor laminated claystone.  Age from date of Trm intrusive and lithologic and stratigraphic similarities to Keno Hill Quartzite in Yukon.","","","TN003","6530","Tanana","Metamorphic","6530","Mg","",""
    "Sls","Thin-bedded limestone","Silurian (latest Llandoverian to early Wenlockian)","Dark-gray to black platy limestone and limy shale.","graptolites","","MD002","505","Medfra","Sedimentary","6620","Sls","",""
    "DSp","Paradise Fork Formation","Early Devonian and Silurian","Deep-water turbiditic and hemipelagic deposits of dark, thin-bedded, fissile to laminated limestone, limy shale, and siltstone.  The formation has an abundant graptolite, conodont, and ostracod fauna.  It was originally assigned an Early to Late Silurian age by Dutro and Patton (1982), but subsequent investigations by Dumoulin and others (1997) indicate that it ranges from Silurian to Early Devonian","","","MD004","4504","Medfra","Sedimentary","6620","","",""
    "pCa","Amy Creek unit of Weber and others (1992)","Late Proterozoic? to early Cambrian?, Devonian?","White, massive, locally laminated, unfossiliferous cherty dolostone characterized by replacement silica boxwork locally and gray limestone at top and bottom of section.  Possible other correlations suggest this unit is equivalent to unit Dld of this quadrangle and age of Devonian, which would simply some regional stratigraphic and structural issues.","","","TN003","6680","Tanana","Sedimentary","6680","SZa","",""
    "Pzvs","Volcanic and sedimentary rocks","Ordovician or Silurian","Partly altered mafic lava and tuff, slate, slaty shale, phyllite, tuffaceous limestone, cherty schist, and chert.  Not on OFR98-133","","","TN002","6910","Tanana","Metamorphic","6910","Dt","",""
    "Pzc","Calcareous clastic rocks","early Paleozoic, possibly Devonian","Medium-gray siltstone and very fine-grained sandstone, largely calcareous and generally schistose.  Not on OFR98-133","","","TN002","6921","Tanana","Metamorphic","6921","Dq?","",""
    "Pzw","Quartz wacke","early Paleozoic, possibly Devonian","Poorly sorted sandstone, granule conglomerate, siltstone, and semischist.  Not on OFR98-133","","","TN002","6922","Tanana","Metamorphic","6922","Dq2?","",""
    "Pzl","Limestone, dolomite, greenstone, and schist","Silurian or Devonian","Limestone, dolomitic limestone, partly silicified dolomite, basaltic greenstone, and chloritic schist.  Similar to unit Pzl south of Yukon River.","","","TN002","6956","Tanana","Metamorphic","6956","DSls?","",""
    "DSl","Reefy limestone and dolomite","Late Silurian, Early Devonian (Siegenian-Emsian), early Late Devonian (Frasnian)","Unit composed of a lower sequence of dolomite containing ostracodes of probable Late Silurian age, a middle sequence of mixed limestone and dolomite having favostid reefs and shelly fossils of probable Early Devonian age and an upper sequence of Amphipora-bearing dolomite and rugose coral bearing limestone","ostracodes, favostid, Ampihpora, Smithiphyllum","","MD002","504","Medfra","Sedimentary","6960","DSwc","",""
    "DSw","Whirlwind Creek Formation","Silurian to Devonian","Shallow water deposits consisting of several repeated cycles.  In the lower part of the formation the cycles grade from algal laminated dolomite into pelletoidal limestone and then into silty limestone and siltstone.  In the upper part  the cycles grade from thick-bedded reefy limestone into thin-bedded limestone.","The formation contains an abundant Late Silurian and Devonian  conodont, brachiopod, coral, and ostracod fauna.","","RB009","835","Ruby","Sedimentary","6960","DSw","",""
    "Pzl","Limestone, greenstone, and schist","Ordovician(?), Silurian, and Devonian","Dominantly light- to light-medium-gray partly dolomitic limestone and dolomite.  Basaltic greenstone and partly calcareous chloritic schist are associated sequentially or interbedded with the carbonate rocks","","","TN002","6966","Tanana","Metamorphic","6966","DSt?","",""
    "Df","Felsic schist","Devonian","Schistose felsic volcanic rocks, including flows, tuffs, and porphyritic hypabyssal? rocks, interlayered with metasedimentary rocks belonging to units  |<sa and |ca.  An important component of this unit is the widely recognized ""button schist"" -a porphyritic rhyolite composed of quartz megacrysts and albite porphyroblasts in a groundmass of quartz, potassium feldspar, and muscovite.","","Unit yielded Devonian U/Pb and Pb/Pb zircon crystallization ages and is interlayered with carbonate rocks containing fossils of probable middle Paleozoic age.","SP003","708","Survey Pass","Metamorphic","7261","Davf","",""
    "Df","Felsic schist","Devonian","Schistose felsic volcanic rocks, including flows, tuffs, and porphyritic hypabyssal? rocks, interlayered with metasedimentary rocks belonging to units  |<sa and |ca.  An important component of this unit is the widely recognized ""button schist"" -a porphyritic rhyolite composed of quartz megacrysts and albite porphyroblasts in a groundmass of quartz, potassium feldspar, and muscovite.","","Unit yielded Devonian U/Pb and Pb/Pb zircon crystallization ages and is interlayered with carbonate rocks containing fossils of probable middle Paleozoic age.","WI003","124","Wiseman","Metamorphic","7261","Davf","",""
    "Dcs","Calcareous schist","Devonian","Light-brown weathering calcareous schist interbedded with gray quartz-mica schist and marble.  Brooks Range schist belt.","","","WI004","","Wiseman","Metamorphic","7350","Pzsb","",""
    "DOtu","Metasedimentary and metavolcanic rocks of Tukpahlearik Creek, undivided","Devonian to Ordovician","Black carbonaceous quartzite and silicieous argillite with lenses of dolostone and marble, silvery gray to silvery green pelitic schist, gray chert pebble metaconglomerate, green calc-schist, micaceous marble, dark green mafic metavolcanic rocks, gray or white metachert, and gray- to white-weathering marble.  Greenschist and blueschist faceis metamorphism.","Ordovician conodonts and Devonian to Ordovician conodonts","","SE003","7450","Selawik","Metamorphic","7450","DOtu","",""
    "DOtu","Metasedimentary and metavolcanic rocks of Tukpahlearik Creek, undivided","Devonian to Ordovician","Black carbonaceous quartzite and siliceous argillite with lenses of dolostone and marble, silvery gray to silvery green pelitic schist, gray chert pebble metaconglomerate, green calc-schist, orange-weathering micaceous marble, dark green mafic metavolcanic rocks, gray or white metachert and gray- to white-weathering marble.  May be coeval with Pzbq, Pzbs, Pzqs, PzPku, PzPks, and PzPkc.","Devonian to Ordovician conodonts","","BM002","616","Baird Mountains","Metamorphic","7450","DOtu","",""
    "DOtq","Carbonaceous quartzite and quartz conglomerate of Tukpahlearik Creek","Devonian(?) to Ordovician","Black carbonaceous quartzite, gray chert pebble metaconglomerate, and quartz schist with minor intercalated lenses of gray marble, micaceous marble, dolostone, and grey quartz mica schist.  May be correlative with Pzbq.","Ordovician conodonts","","BM002","617","Baird Mountains","Metamorphic","7451","","",""
    "DOtmq","Marble and quartz schist of Tukpuhlearik Creek","Devonian to Ordovician","Greenish gray, gray, or green, fine- to medium-grained chloritic quartz schists and siliceous chlorite schists.","","","BM002","619","Baird Mountains","Sedimentary","7453","","",""
    "DOtpg","Pelitic schist and greenstone of Tukpaklearik Creek","Devonian to Ordovician","Green and gray pelitic schists identical to the schist of unit DOtp with intercalated masses of dark green metabasite, mafic dikes, mafic extrusive rocks and white metachert.","","","BM002","621","Baird Mountains","Metamorphic","7454","","",""
    "DOtp","Pelitic schists of Tukpaklearik Creek","Devonian to Ordovician","Greenish-gray, green, or gray fine- to medium-grained chloritic quartz schist and siliceous chlorite schist","","","BM002","620","Baird Mountains","Metamorphic","7455","DOtp","",""
    "Ol","Limestone and dolomite","Ordovician","Dark-gray limestone and brownish-yellow dolomite. Dolomite is common near base of section.   Lies unconformably on older metamorphic rocks.  Massive unit overlain by thinner bedded limestone and dolomite, succeeded by the thickest beds of the series.  Total thickness of 6000 to 8000 feet for the Ordovician series.  Locally silicified, dolomitized, and recrystallized.","","","RB002","901","Ruby","Sedimentary","7520","Ont","",""
    "Od","Massive dolomite and limestone","Middle to Late Ordovician (White Rockian to Maysvillian)","Light-brown to dark-gray massive dolomite and limestone cyclically interbedded with shallow-water yellowish-orange-weathering algal and lime mudstone.","Gastropods, corals, brachiopods, ostracodes, conodonts","","MD002","506","Medfra","Sedimentary","7520","Ont","",""
    "Osl","Silty limestone and siltstone","Early Ordovician","Chiefly yellowish-orange-weathering, thin-bedded, shallow-water, silty limestone and limy siltstone.","Conodonts, trilobites, gastropods, cephalopods","","MD002","507","Medfra","Sedimentary","7520","Ont","",""
    "Ont","Novi Mountain and Telstina Formations","Ordovician","Novi Mountain Formation: Shallow water deposits.  Predominately calcareous siltstone and shale in lower part.  Upper part characterized by cycles beginning with massive limestone commonly containing flat carbonate pebbles at the base and grading upward through thin irregularly bedded shaly limestone into calcareous siltstone or shale at the top.
Telsitna Formation: Chiefly shallow water limestone and dolomite.  The lower part dominated by highly fossiliferous thin-bedded fine-grained limestone containing silty interbeds.  Middle part consists chiefly of nonfossiliferous dolomite.  The upper part is composed mainly of limestone that ranges from thick bedded and fine-grained to thin-bedded and silty.  Stringers and nodules of black chert occur near the top.  The upper part locally is characterized by platy dark limestone containing conodonts indicative of deep-water deposition.   ","The Novi Mountain Formation contains a sparse Early Ordovician conodont fauna. The Telstina Formation contains an abundant conodont, brachiopod, and coral fauna.  It was  originally assigned a Middle and Late Ordovician age by Dutro and Patton (1982), but subsequent investigations by Dumoulin and others (1997) indicate that it ranges from Early to Late Ordovician.","","RB009","830","Ruby","Sedimentary","7520","Ont","",""
    "Ont","Novi Mountain and Telsitna Formations, undivided ","Ordovician","Novi Mountain Formation: Shallow water deposits.  Predominately calcareous siltstone and shale in lower part.  Upper part characterized by cycles beginning with massive limestone commonly containing flat carbonate pebbles at the base and grading upward through thin irregularly bedded shaly limestone into calcareous siltstone or shale at the top. 
Telsitna Formation: Chiefly shallow water limestone and dolomite.  The lower part dominated by highly fossiliferous thin-bedded fine-grained limestone containing silty interbeds.  Middle part consists chiefly of nonfossiliferous dolomite.  The upper part is composed mainly of limestone that ranges from thick bedded and fine-grained to thin-bedded and silty.  Stringers and nodules of black chert occur near the top.","[Novi Mountain Formation] contains a sparse Early Ordovician conodont fauna. The upper part [of Telsitna Formation] locally is characterized by platy dark limestone containing conodonts indicative of deep-water deposition.  The formation contains an abundant conodont, brachiopod, and coral fauna.  It was  originally assigned a Middle and Late Ordovician age by Dutro and Patton (1982), but subsequent investigations by Dumoulin and others (1997) indicate that it ranges from Early to Late Ordovician.

 

","","MD004","507","Medfra","Sedimentary","7520","","",""
    "Ont","Novi Mountain and Telsitna Formations, undivided ","Ordovician","Novi Mountain Formation: Shallow water deposits.  Predominately calcareous siltstone and shale in lower part.  Upper part characterized by cycles beginning with massive limestone commonly containing flat carbonate pebbles at the base and grading upward through thin irregularly bedded shaly limestone into calcareous siltstone or shale at the top. 
Telsitna Formation: Chiefly shallow water limestone and dolomite.  The lower part dominated by highly fossiliferous thin-bedded fine-grained limestone containing silty interbeds.  Middle part consists chiefly of nonfossiliferous dolomite.  The upper part is composed mainly of limestone that ranges from thick bedded and fine-grained to thin-bedded and silty.  Stringers and nodules of black chert occur near the top.","[Novi Mountain Formation] contains a sparse Early Ordovician conodont fauna. The upper part [of Telsitna Formation] locally is characterized by platy dark limestone containing conodonts indicative of deep-water deposition.  The formation contains an abundant conodont, brachiopod, and coral fauna.  It was  originally assigned a Middle and Late Ordovician age by Dutro and Patton (1982), but subsequent investigations by Dumoulin and others (1997) indicate that it ranges from Early to Late Ordovician.

 

","","MD004","701","Medfra","Sedimentary","7520","","",""
    "Pzc","Chert and phyllite","early Paleozoic","Banded light-gray to black sooty impure radiolarian chert, green talcy phyllite and slate, thin-bedded shaly limestone, and calcareous quartzite.","","","MD002","509","Medfra","Metamorphic","7581","SCpl","",""
    "Oc","Chert and phyllite","early Paleozoic","Banded light-gray to black sooty impure radiolarian chert, green talcy phyllite and slate, thin-bedded shaly limestone, and calcareous quartzite.  Reassignment of rocks originally assigned to unit Pzc in the Minchumina terrane to unit Oc","Unit locally contains conodonts and graptolites of Early and Middle Ordovician age in the Medfra quadrangle and east of the map area in adjoining parts of the Mt. McKinley quadrangle","","MD004","5509","Medfra","Metamorphic","7581","Oc","",""
    "Oc","Chert and argillite","Ordovician","Banded chert, argillite, fine-grained thin-bedded limestone, and silty dolomite.  Beds separated by carbonaceous partings.  Unit interpreted to be a deep-water sequence composed of turbiditic and hemipelagic deposits.","Unit locally contains conodonts and graptolites of Early and Middle Ordovician age in the Medfra quadrangle and east of the map area in adjoining parts of the Mt. McKinley quadrangle","","RB009","829","Ruby","Metamorphic","7581","Oc","",""
    "Ofc","Fossil Creek Volcanic unit of Weber and others (1992)","Ordovician","Agglomeratic mafic volcanic rocks, volcaniclastic rocks, and assoiciated argillaceous sedimentary rocks","","","TN003","7610","Tanana","Igneous","7610","Ofc","",""
    "Oc","Chert","Late(?) Ordovician","Light- to medium-gray chert.","","","TN002","7710","Tanana","Metamorphic","7710","Och","",""
    "Pzlc","Livengood Dome Chert?","Ordovician","Heterogeneous, low-grade, blastomylonitic assemblage of silicieous to cherty argillite, recrystallized chert, intermediate to mafic volcaniclastic rocks and greenstone, graywacke, grit, and oolitic limestone.  Resembles lower grade parts of unit Pzs in this quadrangle.","","","TN003","7712","Tanana","Metamorphic","7710","Och","",""
    "Olc","Livengood Dome Chert","Ordovician","Separate from Pzlc which was described as:  Heterogeneous, low-grade, blastomylonitic assemblage of silicieous to cherty argillite, recrystallized chert, intermediate to mafic volcaniclastic rocks and greenstone, graywacke, grit, and oolitic limestone.  Resembles lower grade parts of unit Pzs in this quadrangle.  No new description provided for this, see Livengood, unit Old)","","","TN003","7710","Tanana","Metamorphic","7710","Och","",""
    "Pzll","Limestone","Paleozoic?","Distinctive marker bed of lime mudstone, locally characterized by coated ooids; is part of Livengood Dome Chert","","","TN003","7711","Tanana","Sedimentary","7711","Oldl","",""
    "PzpCq","Quartzite, grit, and argillite","early Paleozoic or preCambrian","Fine- to coarse-grained quartzite, quartz grit, quartz-feldspar grit, and argillite grading upward in to very fine grained quartzite, argillite, calcareous argillite, phyllite, and chert.","","","MD002","601","Medfra","Metamorphic","8300","CZw","",""
    "PzpCs","Quartzite, grit, and argillite","early Paleozoic or preCambrian","Sheared and foliated quartz and quartz-feldspar grits and quartzite intercalated with quartz-muscovite-chlorite and quartz-muscovite-biotite schists.  Subordinate phyllite, thin limestone, and metachert.","","276 Ma K-Ar muscovite and 421 Ma K-ar(?) hornblende on intrusion (?) to unit.","MD002","602","Medfra","Metamorphic","8300","","",""
    "pCw","Wickersham unit of Weber and others (1992), undivided","Cambrian and or Late Proterozoic","Poorly sorted quartzite and grit, having abundant quartz and plagioclase clasts in a quartzofeldspathic-wacke matrix.","","","TN003","8410","Tanana","Metamorphic","8300","CZwa","",""
    "Cal","Argillite, slate, quartzite and grit","probably Cambrian, possibly in part preCambrian","Medium- to dark-red or maroon, light- to medium-green and grayish-green, and medium-gray argillite and slate.  Light yellow-brown to light-gray quartzite and grit.  Not on OFR98-133","","","TN002","8410","Tanana","Metamorphic","8310","CZwa","",""
    "PzPi","Meta-intrusive rocks of intermediate composition","Paleozoic and (or) Proterozoic","White, light gray, or green and white, massive to gneissic, granitic to dioritic meta-intrusive rocks.","","Muscovite K-Ar of 107 Ma, biotite K-Ar of 95.9 Ma, biotite K-Ar of 96 +/- 1.2 Ma","BM002","813","Baird Mountains","Metamorphic","8500","PzZi","",""
    "PzZi","Gneissic granite","Paleozoic? and Proterozoic","Granite, granodiorite, diorite, and gabbro that have  a slight to moderate gneissic fabric.  The northwesternmost of the two bodies is Proterozoic  and has yielded a U/Pb zircon crystallization  age of 705 Ma.   The southeasternmost body is of uncertain age.  It may also be Proterozoic or it may be Devonian and correlative with unit Dgna","","","BM003","1004","Baird Mountains","Metamorphic","8500","PzZi","",""
    "mca","Metamorphic complex","Precambrian or Paleozoic","In eastern part of quad, metamorphic complex mapped as two units, mca and mcb.   The older unit, mca is composed of crystalline limestone and greenstone with some schist and phyllite. (Assigned to Ruby terrane.)","","","RB002","504","Ruby","Metamorphic","8601","PzZrqs","",""
    "PzpCs/TrMc","None","Uncertain","Map shows questionable identification of unit. (Assigned to Ruby terrane.)","","","OP002","901","Ophir","Metamorphic","8601","PzZrqs","",""
    "PzpCsq","Schist, quartzite, phyllite, and slate","early Paleozoic(?) and preCambrian(?)","Light- to medium-gray and silvery gray quartz-mica schist, light- to medium-gray quartzite, light- to dark-gray slate and phyllite.  Not on OFR98-133","","","TN002","8630","Tanana","Metamorphic","8601","PzZrqs","",""
    "PzpCs","Pelitic Schist","Precambrian and/or Paleozoic","Fine- to medium-grained graphitic quartz-muscovite +/- chlorite schist.  Minerology consistent with greenschist facies metamorphism. (Assigned to Ruby terrane.)","","","RB005","118","Ruby","Metamorphic","8601","PzZrqs","",""
    "mcb","Metamorphic complex","Precambrian or Paleozoic","The younger unit, mcb, contains schist and quatzite with some crystalline limestone, slate, and greenstone.  Part of unit recorrelated (D.N. Bradley, USGS, pers commun., 1998)","","","RB002","503","Ruby","Metamorphic","8601","SCpl","",""
    "PzpCs","Greenschist and quartz mica schist","early Paleozoic or preCambrian","Medium-gray to medium-green, medium- to coarse-grained, schistose, foliated, actinolite-chlorite-epidote greenschist and biotite-chlorite-albite-quartz schist. (Assigned to Ruby terrane.)","","","MD003","8601","Medfra","Metamorphic","8601","PzZrqs","",""
    "TrMs","None","Triassic, Permian, Pennsylvanian, and Mississippian","Sandstone, grit, and argillite -- some polygons in northeast part of map reassigned to unit PzpCph, per Bundtzen and others (1997). (Assigned to Ruby terrane.)","","","OP003","601","Ophir","Sedimentary","8601","PzZrqs","",""
    "Pzqs-s","Schist","Paleozoic?","Stipple pattern added to Pzqs on Dovers map; nature of unit to be determined.  Low to  moderately high-grade, blastomylonitic, polymetamorphic assemblage of pelitic to quartzitic schist containing subordinate layers of quartzo-feldspathic schist, calc-schist, calc-sliciate gneiss, amphibolitic schist, quartzite, marble, and metaconglomerate.  (Shown on source map compilation as Pzqs)","","","TN007","9000","Tanana","Metamorphic","8601","PzZrqs","",""
    "PzPs","Phyllite","Paleozoic and Proterozoic","Phyllite and subordinate fine-grained metagraywacke cut by abundant vein quartz.  The phyllite and metagraywacke are overprinted by a low-grade penetrative metamorphic fabric, but turbidite features, such as sole marks and graded bedding, are locally discernible.  Age of unit is uncertain,  probably Devonian or late Paleozoic.  Correlative with unit |pa in the Arctic Alaska terrane","","","RB009","833","Ruby","Metamorphic","8601","PzPs","",""
    "Pzq","Quartzite","Paleozoic (?)","Gray massive quartzite with subordinate quartz-mica schist","","","WI004","175","Wiseman","Metamorphic","8602","PzZrqs","",""
    "PzpCku","Mixed schists of the Kallarichuk Hills, undivided","Paleozoic and (or) Proterozoic","Silvery green and gray quartz-mica schist, brown calcareous schist, gray marble, and black quartzite.  Carbonaceous rocks compose 20 percent of unit, marble less than 1 percent.  Indicate blueschist metamorphism followed by retrograde greenschist facies metamorphism.","Mississippian to Silurian conodonts","Proterozoic U-Pb age on zircon from granodiorite intruding marble, and K-Ar cooling ages of 114 Ma on muscovite and 91.6 Ma on biotite.","SE003","8650","Selawik","Metamorphic","8602","PzZmc","",""
    "PzZsa","Pelitic schist, calc schist, and quartzite","Paleozoic and Proterozoic","Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albiteglaucophane   assemblages. A relict epidote-amphibolite metamorphic assemblage suggests that, at locally, the unit underwent a pre-mid Devonian metamorphic event.  Unit is interbedded with carbonate rocks of unit Pzca and therefore is, in part, Paleozoic in age.  However, in the Baird Mountains quadrangle, unit is intruded by Proterozoic granitic rocks of unit PzZi, and therefore is locally as old as Proterozoic. 
","","K/Ar isotopic analyses of the schist yielded Early Cretaceous metamorphic mineral cooling ages. ","SP003","707","Survey Pass","Metamorphic","8602","","",""
    "PzZsa","Schist and quartzite","Paleozoic and Proterozoic","Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albiteglaucophane   assemblages. A relict epidote-amphibolite metamorphic assemblage suggests that, at locally, the unit underwent a pre-mid Devonian metamorphic event.  Unit is interbedded with carbonate rocks of unit Pzca and therefore is, in part, Paleozoic in age.  However, in the Baird Mountains quadrangle, unit is intruded by Proterozoic granitic rocks of unit PzZi, and therefore is locally as old as Proterozoic. ","","K/Ar isotopic analyses of the schist yielded Early Cretaceous metamorphic mineral cooling ages","AR003","714","Ambler River","Metamorphic","8602","PzZrqs","",""
    "PzZsa","Schist and quartzite","Paleozoic and Proterozoic","Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albite  glaucophane assemblages. A relict epidote-amphibolite metamorphic assemblage suggests that, at locally, the unit underwent a pre-mid Devonian metamorphic event.  Unit is interbedded with carbonate rocks of unit Pzca and therefore is, in part, Paleozoic in age.  However, in the Baird Mountains quadrangle, unit is intruded by Proterozoic granitic rocks of unit PzZi, and therefore is locally as old as Proterozoic
","","Samples of the schist yielded a metamorphic mineral K/Ar isotopic cooling age of 124 Ma.","BM003","1002","Baird Mountains","Metamorphic","8602","PzZs","",""
    "PzZsa","Pelitic schist, calc schist, and quartzite","Paleozoic and Proterozoic","Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albiteglaucophane assemblages. A relict epidote-amphibolite metamorphic assemblage suggests that, at locally, the unit underwent a pre-mid Devonian metamorphic event.  Unit is interbedded with carbonate rocks of unit Pzca and therefore is, in part, Paleozoic in age.  However, in the Baird Mountains quadrangle, unit is intruded by Proterozoic granitic rocks of unit PzZi, and therefore is locally as old as Proterozoic. 
","","K/Ar isotopic analyses of the schist yielded Early Cretaceous metamorphic mineral cooling ages","SE004","3001","Selawik","Metamorphic","8602","","",""
    "PzZsa","Pelitic schist, calc schist, and quartzite","Paleozoic and Proterozoic","Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albiteglaucophane   assemblages. A relict epidote-amphibolite metamorphic assemblage suggests that, at locally, the unit underwent a pre-mid Devonian metamorphic event","","K/Ar isotopic analyses of the schist yielded Early Cretaceous metamorphic mineral cooling ages","SH004","714","Shungnak","Metamorphic","8602","","",""
    "Pzs","Pelitic schist","Paleozoic and Precambrian (?)","Pelitic schist including quartz-mica schist, chlorite schist, quartzo-feldspathic schist, and subordinate quartzite; metamorphic grade range of lower greenschist to almandine-amphibolite facies; local hornfels","","","WI004","170","Wiseman","Metamorphic","8602","PzZrqs","",""
    "PzZsr","Pelitic schist, calc schist, and quartzite ","Paleozoic and Proterozoic?","Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albiteglaucophane   assemblages. A relict epidote-amphibolite metamorphic assemblage suggests that, at locally, the unit underwent a pre-mid Devonian metamorphic event.  Unit is interbedded with carbonate rocks of unit Pzca and therefore is, in part, Paleozoic in age.  However, in the Baird Mountains quadrangle, unit is intruded by Proterozoic granitic rocks of unit PzZi, and therefore is locally as old as Proterozoic","","K/Ar isotopic analyses of the schist yielded Early Cretaceous metamorphic mineral cooling ages","WI003","127","Wiseman","Metamorphic","8602","","",""
    "Pzp","Dark phyllite and fine-grained quartz-mica schist","late Paleozoic and early Mesozoic or pre-Devonian","Chiefly dark phyllite and fine-grained quartz-mica schist.  Unit underlies, overlies and interfingers with limestone and dolomite (unit Pzl).  Upper part may be late Paleozoic and early Mesozoic and lowest part may be pre-Devonian in age","","","SH002","19","Shungnak","Metamorphic","8605","Pzpq","",""
    "Pzs","Schist and phyllite","middle Paleozoic","Chiefly light- to dark-gray fine-grained quartz-mica schist and grayish-black phyllite.  Subordinate calcareous schist, limestone, chlorite schist, and amphibolite schist.  May locally include metasedimentary rocks of middle Cretaceous age.","","","SE002","300","Selawik","Metamorphic","8605","Pzpq","",""
    "PzPku","Mixed schists of the Kallarichuk Hills, undivided","Paleozoic and (or) Proterozoic","Silvery green and gray quartz-mica schists, brown calcareous schists, gray marble and black quartzite.","conodonts","Zircon U-Pb age, K-Ar age of 91.6 +/- 1.5 Ma from biotite","BM002","809","Baird Mountains","Metamorphic","8605","","",""
    "PzPkc","Calcareous schist and marble of the Kallarichuk Hills","Paleozoic and (or) Proterozoic","Tan to brown calcareous quartz-mica schist, gray quartz-albite-mica schist, black carbonaceous schist, and lenses of massive gray marble tens of meters thick.","","Zircon U-Pb of 705 +/- 35 Ma","BM002","811","Baird Mountains","Metamorphic","8605","","",""
    "PzPcb","Carbonate rocks and metabasite","Paleozoic and (or) Proterozoic","Orange- to light-gray-weathering, dark-to light-gray, fine- to medium-grained crystalline dolostone, metalimestone and marble, with subordinate intercalated calcareous quartzite, quartz-mica schist, green and silver phyllite, carbonate cobble metaconglomerate, and blue amphibole-bearing metabasite.","","","BM002","812","Baird Mountains","Metamorphic","8605","","",""
    "PzZu","Schist and carbonate rocks, undifferentiated","Paleozoic and Proterozoic","Pelitic schist, calc schist, and quartzite (PzZsa) and carbonate rocks (Pzca), undivided","","","BM003","1003","Baird Mountains","Metamorphic","8605","Pzls","",""
    "PzZua","Pelitic schist, calc schist, and quartzite (PzZsa) and carbonate rocks (Pzca), undivided","Paleozoic and Proterozoic","Pelitic schist, calc schist, and quartzite (PzZsa) and carbonate rocks (Pzca), undivided","","","SE004","3020","Selawik","Metamorphic","8605","","",""
    "PzPks","Siliceous schist of the Kallarichuk Hills","Paleozoic and (or) Proterozoic","Light silvery gray to silvery grayish green to dark green garnet-mica-quartz schists.","","Muscovite  K-Ar of 116 +/- 2.5 Ma, glaucophane K-Ar of 767 Ma, actinolite K-Ar of 660 Ma and 632 Ma ","BM002","810","Baird Mountains","Metamorphic","8606","","",""
    "mcl","Metamorphic complex","Precambrian or Paleozoic ( may contain Ordovician and Devonian) ","Crystalline limestone, may  include rocks of Ordovican or Devonian but generally is more recystallized than Ordovican or Devonian rocks and is associated with schists.","","","RB002","502","Ruby","Metamorphic","8610","Pzrm","",""
    "mcb","Metamorphic complex","Precambrian or Paleozoic","In the eastern part of quadrangle, the metamorphic complex mapped as two units, mca and mcb.   The younger unit, mcb, contains schist and quartzite with some crystalline limestone, slate, and greenstone.","","","RB002","503","Ruby","Metamorphic","8610","YZnm","",""
    "PzpCc","Calc-schist","early Paleozoic or preCambrian","Light to medium-gray calc-schist and thin-bedded schistose impure marble  White to light-gray, fine-grained massive sandy marble.  Subordinate quartz-mica schist.","","","MD002","604","Medfra","Metamorphic","8610","YZnc","",""
    "Pztbl","Tamarack Bluff Limestone","Paleozoic (?)","Marble and recrystallized limestone, dominantly fine- to coarse-grained calcitic marble, with some sedimentary structures preserved.  Probably correlative with Ruby Marble","","","RB005","116","Ruby","Metamorphic","8610","Pzrm","",""
    "mca","Metamorphic complex","Precambrian or Paleozoic","In the eastern part of quadrangle, the metamorphic complex mapped as two units, mca and mcb.   The older unit, mca is composed of crystalline limestone and greenstone with some schist and phyllite.","","","RB002","504","Ruby","Metamorphic","8610","YZnm","",""
    "Zc","Calc-schist, quartz-mica schist, and greenstone","Proterozoic","Calc-schist, thin bedded schistose impure marble, and fine-grained massive sandy marble.  Contains subordinate quartz-mica schist and small bodies of greenstone.  Unit underlies unit Ont and gradationally overlies unit Zs","","","RB009","831","Ruby","Metamorphic","8610","YZnc","",""
    "mc","Metamorphic complex","Precambrian or Paleozoic","Schist, crystalline limestone, quartzite, greenstone, slate, and phyllite.  Areas of crystalline limestone mapped separately when possible as mcl.","","","RB002","501","Ruby","Metamorphic","8625","PzZrqs","",""
    "mc","Metamorphic complex","Late Precambrian or  Early Paleozoic","Quartz-mica schist, quatzite-schist, mica schist, albite-chlorite schist, albite-mica schist, ottrelite-mica schist, glaucophane-mica schist, some phyllite, slate, sheared chert, and quartzite.  Unit superceded.","","","NL002","501","Nulato","Metamorphic","8625","PzZm","",""
    "PzpCs","Schistose metamorphic rocks","Early Paleozoic or Late Precambrian","Schistose metamorphic rocks","","","OP002","802","Ophir","Metamorphic","8625","PzZrqs","",""
    "PzZs","Schist and quartzite","Paleozoic and Proterozoic?","Consists cheifly of quartzite, quartz-mica schist, chlorite schist, and micaceous and graphitic quartzite.  also include unknown thicknesses of or poorly exposed fine-grained pelitic schist and phyllite.","","","NL003","8650","Nulato","Metamorphic","8625","","",""
    "PzZsr","Pelitic schist, calc schist, and quartzite ","Paleozoic and Proterozoic?","Quartz-mica schist, chlorite schist, quartzofeldspathic schist, quartzite, and micaeous and graphitic schist.  Regionally metamorphosed to greenschist-facies, but also locally includes high-pressure greenschist-blueschist-facies (distinguished by the presence of glaucophane) and amphibolite-facies (distinguished by the presence of sillimanite and kyanite).  Andalusite-cordierite hornfels and contact schist occur in broad bands around Cretaceous granitic bodies of units Kgr and Ksy.  Unit locally is interlayered with carbonate rocks of unit Pzcr and therefore is, at least in part, Paleozoic in age.  However, some of the unit may be as old as Proterozoic.  The regional metamorphism clearly pre-dates the widespread intrusion of the Early Cretaceous granitic bodies of units Kgr and Ksy. ","","Metamorphic minerals in this unit in the Nulato quadrangle yielded  K/Ar isotopic cooling ages of 134 and 136 Ma. ","OP005","5802","Ophir ","Metamorphic","8625","","",""
    "PzZsr","Pelitic schist, calc schist, and quartzite ","Paleozoic and Proterozoic?","Quartz-mica schist, chlorite schist, quartzofeldspathic schist, quartzite, and micaeous and graphitic schist.  Regionally metamorphosed to greenschist-facies, but also locally includes high-pressure greenschist-blueschist-facies (distinguished by the presence of glaucophane) and amphibolite-facies (distinguished by the presence of sillimanite and kyanite).  Andalusite-cordierite hornfels and contact schist occur in broad bands around Cretaceous granitic bodies of units Kgr and Ksy.  Unit locally is interlayered with carbonate rocks of unit Pzcr and therefore is, at least in part, Paleozoic in age.  However, some of the unit may be as old as Proterozoic.  The regional metamorphism clearly pre-dates the widespread intrusion of the Early Cretaceous granitic bodies of units Kgr and Ksy.","","Metamorphic minerals in this unit in the Nulato quadrangle yielded  K/Ar isotopic cooling ages of 134 and 136 Ma. ","TN008","38625","Tanana","Metamorphic","8625","","",""
    "PzpCp","Pelitic schist","early Paleozoic or preCambrian","Chiefly pelitic and quartzose metasedimentary rocks of greenschist facies.  Light-gray micaceous quartzite and greenish quartz-chlorite-muscovite schist grading into dark-gray quartz-muscovite-biotite-garnet schist.  Subordinate calc schist and marble.  Locally includes greenstone and greenschist metamorphic igneous rocks composed of chlorite, epidote, actinolite, and plagioclase.  Also includes a small body of pink granitic gneiss","","K-Ar mica ages from 274-514 Ma, correlatives as old as 921 Ma","MD002","605","Medfra","Metamorphic","8640","YZns","",""
    "Zs","Pelitic schist, quartzite, quartzo-feldspathic gneiss, and greenstone","Proterozoic","Chiefly pelitic and quartzose metasedimentary rocks of greenschist metamorphic facies.  Micaeous quartzite and quartz-chlorite schist grade into quartz-muscovite-biotite-garnet     schist.  Subordinate calc schist and marble.  Unit locally includes small bodies of greenstone and greenschist metabasite,  granitic gneiss,  and metamorphosed quartz porphyry","","Zircon fractions from two samples of metamorphosed quartz porphyry indicate a crystallization age of 1,26550 Ma.  Metamorphic minerals from the schist yield K/Ar isotopic cooling ages that range from 921 to 296 Ma","RB009","834","Ruby","Metamorphic","8640","","",""
    "Zs","Pelitic schist, quartzite, quartzo-feldspathic gneiss, and greenstone ","Proterozoic","Chiefly pelitic and quartzose metasedimentary rocks of greenschist metamorphic facies.  Micaeous quartzite and quartz-chlorite schist grade into quartz-muscovite-biotite-garnet schist.  Subordinate calc schist and marble.  Unit locally includes small bodies of greenstone and greenschist metabasite,  granitic gneiss,  and metamorphosed quartz porphyry.","","Zircon fractions from two samples of metamorphosed quartz porphyry indicate a crystallization age of 1,26550 Ma.  Metamorphic minerals from the schist yield K/Ar isotopic cooling ages that range from 921 to 296 Ma. ","MD004","4605","Medfra","Metamorphic","8641","","",""
    "PzpCv","Metavolcanic rocks","early Paleozoic or preCambrian","Tan, light-gray, pink, and green banded fine-grained felsic volcanic rocks having well-developed foliation.  Chiefly porphyry composed of large phenocrysts of embayed quartz and plagioclase in a very fine grained quartzo-feldspathic groundmass which has a distinct micaeous overprint.","","","MD002","603","Medfra","Metamorphic","8700","YZnv","",""
    "ira","Intrusive rocks","Pre-Cretaceous","Granite, monzonite and diorite altered to augen gniess and mica schist.  Locally contains younger granitic dikes.","","","RB002","702","Ruby","Metamorphic","8710","PzZrqs","",""
    "pCm","Meta-quartz diorite","middle Proterozoic?","Sheared metamorphosed porphyritic quartz diorite","","K-Ar on biotite 921 +/- 25 Ma, mouscovite in border zone 663+/- 20 Ma","RB007","8710","Ruby","Metamorphic","8710","Ynqd","",""
    "PzpCn","Gneiss and quartzite","Paleozoic or Precambrian","Quartz-feldspar-biotite gneiss commonly garnetiferous and locally contains sillimanite.  Almandine-amphibolite facies metamorphism.  Some augen gneiss.  Gray coarse-grained quartzite with thin layers of biotite.  Subordinate quartz-mica schist, marble, and calc-silicate rock.  Contacts with PzpCs and Km are gradational and indefinite.  Appears to underlie PzpCs.  ","","","MZ002","720","Melozitna","Metamorphic","8801","PzZrpg","",""
    "PzpCqg?","Quartzofeldspathic orthogneiss","Late Proterozoic? and or Paleozoic?","Quartzofeldspathic orthogneiss, located only on west side of Ray Mountains pluton.","","","TN003","8800","Tanana","Metamorphic","8801","Zg","",""
    "PzpCg","Gneissic rocks","Paleozoic or Precambrian","Garnetiferous quartz-feldspar-biotite gneiss of almandine-amphibolite facies.  Also includes some quartzitic gneiss, amphibolitic gneiss, migmatite, small bodies of marble, and a few small bodies of granitic rock. ","","","RB004","8630","Ruby","Metamorphic","8801","PzZrpg","",""
    "PzpCsg","Pelitic Schist and Gneiss","Precambrian and/or Paleozoic","Medium- to coarse-grained quartz +/- muscovite +/- chlorite +/- biotite +/- grapphite +/- garnet +/- staurolite schist, quartzofeldspathic orthogneiss, and foliated greenstone.  Minerology consistent with amphibolite facies metamorphism","","","RB004","119","Ruby","Metamorphic","8801","PzZrpg","",""
    "MzPkc","Gneissic rocks","Paleozoic or Precambrian","Gametiferous quartz-feldspar-biotite gneiss of almandine-amphibolite facies.  Also includes some quartzitic gneiss, amphibolitic gneiss, migmatite, small bodies of marble, and a few small bodies of granitic rock.","","","RB009","825","Ruby","Metamorphic","8801","MzZkc","",""
    "PzpCsg","Pelitic schist and gneiss","Paleozoic and preCambrian","Medium- to coarse-grained quartz+/- muscovite +/- chlorite +/- biotite +/- graphite +/- garnet +/- staurolite schist, quartzofeldspathic orthogneiss, and foliated greenstone.  Probably amphibolite facies metamorphism.","","","RB005","119","Ruby","Metamorphic","8801","","",""
    "PzpCs","Pelitic schist","Paleozoic or Precambrian","Quartz-chlorite-muscovite schist and micaceous quartzite.  Greenschist facies metamorphism.  Subordinate micaceous quartzite and glaucophane-chlorite-muscovite schist.  Unit includes many small bodies of marble, greenstone and greenschist (believed to be altered mafic rocks).","","","MZ002","700","Melozitna","Metamorphic","9325","PzZrqs","",""
    "PzpCm","Metamorphic rocks","Paleozoic and preCambrian?","Not described","","","RB003","8600","Ruby","Sedimentary","9325","PzZrqs","",""
    "Pzs","Schist","Paleozoic?","Low to  moderately high-grade, blastomylonitic, polymetamorphic assemblage of pelitic to quartzitic schist containing subordinate layers of quartzo-feldspathic schist, calc-schist, calc-sliciate gneiss, amphibolitic schist, quartzite, marble, and metaconglomerate.  (Shown on source map compilation as Pzqs)","","","TN003","8630","Tanana","Metamorphic","9325","PzZtqs","",""
    "Pzq","Quartzite","Paleozoic?","Relatively pure quartzite units locally mappable and typically associated with mafic rocks (unit Pzm) and metalimestone and marble (unit Pzl).  (Shown on source map compilation as uncolored Pzqs)","","","TN003","8640","Tanana","Metamorphic","9325","PzZrqs","",""
    "PzpCm","Metamorphic rocks (Pelitic schist)","Paleozoic or Precambrian","Pelitic schist, quartzite, and calcareous to dolomitic marble, generally of greenschist facies.","","","RB004","8600","Ruby","Metamorphic","9325","PzZrqs","",""
    "Pzs","Pelitic schist","Paleozoic and Precambrian (?)","Pelitic schist including quartz-mica schist, chlorite schist, quartzo-feldspathic schist, and subordinate quartzite; metamorphic grade range of lower greenschist to almandine-amphibolite facies; local hornfels","","","BT002","170","Bettles","Metamorphic","9325","PzZrqs","",""
    "mc","Metamorphic complex","Precambrian or Paleozoic","Schist, crystalline limestone, quartzite, greenstone, slate, and phyllite.  Areas of crystalline limestone mapped separately when possible as mcl.","","","RB002","501","Ruby","Metamorphic","9325","PzZrqs","",""
    "PzZsr","Pelitic schist, calc schist, and quartzite","Paleozoic and Proterozoic?","Quartz-mica schist, chlorite schist, quartzofeldspathic schist, quartzite, and micaeous and graphitic schist.  Regionally metamorphosed to greenschist-facies, but also locally includes high-pressure greenschist-blueschist-facies (distinguished by the presence of glaucophane) and amphibolite-facies (distinguished by the presence of sillimanite and kyanite).  Andalusite-cordierite hornfels and contact schist occur in broad bands around Cretaceous granitic bodies of units Kgr and Ksy.  Unit locally is interlayered with carbonate rocks of unit |cr and therefore is, at least in part, Paleozoic in age.  However, some of the unit may be as old as Proterozoic.  The regional metamorphism clearly pre-dates the widespread intrusion of the Early Cretaceous granitic bodies of units Kgr and Ksy.  ","","Metamorphic minerals in this unit in the Nulato quadrangle yielded  K/Ar isotopic cooling ages of 134 and 136 Ma.","BT003","122","Bettles","Metamorphic","9325","PzZrqs","",""
    "PzZsr","Pelitic schist, calc schist, and quartzite ","Paleozoic and Proterozoic?","Quartz-mica schist, chlorite schist, quartzofeldspathic schist, quartzite, and micaeous and graphitic schist.  Regionally metamorphosed to greenschist-facies, but also locally includes high-pressure greenschist-blueschist-facies (distinguished by the presence of glaucophane) and amphibolite-facies (distinguished by the presence of sillimanite and kyanite).  Andalusite-cordierite hornfels and contact schist occur in broad bands around Cretaceous granitic bodies of units Kgr and Ksy.  Unit locally is interlayered with carbonate rocks of unit |cr and therefore is, at least in part, Paleozoic in age.  However, some of the unit may be as old as Proterozoic.  The regional metamorphism clearly pre-dates the widespread intrusion of the Early Cretaceous granitic bodies of units Kgr and Ksy.
","","Metamorphic minerals in this unit in the Nulato quadrangle yielded  K/Ar isotopic cooling ages of 134 and 136 Ma.","WI003","122","Wiseman","Metamorphic","9325","","",""
    "PzZsr","Pelitic schist, calc schist, and quartzite ","Paleozoic and Proterozoic?","Quartz-mica schist, chlorite schist, quartzofeldspathic schist, quartzite, and micaeous and graphitic schist.  Regionally metamorphosed to greenschist-facies, but also locally includes high-pressure greenschist-blueschist-facies (distinguished by the presence of glaucophane) and amphibolite-facies (distinguished by the presence of sillimanite and kyanite).  Andalusite-cordierite hornfels and contact schist occur in broad bands around Cretaceous granitic bodies of units Kgr and Ksy. Unit locally is interlayered with carbonate rocks of unit |cr and therefore is, at least in part, Paleozoic in age.  However, some of the unit may be as old as Proterozoic.  The regional metamorphism clearly pre-dates the widespread intrusion of the Early Cretaceous granitic bodies of units Kgr and Ksy.","","Metamorphic minerals in this unit in the Nulato quadrangle yielded  K/Ar isotopic cooling ages of 134 and 136 Ma.  ","MZ004","700","Melozitna","Metamorphic","9325","","",""