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Mineral Resources > Online Spatial Data > Geology > by state > New Hampshire Geology

Geologic units in Coos county, New Hampshire

Ordovician gabbro/diorite/ultramafic rocks (Ordovician) at surface, covers < 0.1 % of this area

Ordovician gabbro/diorite/ultramafic rocks

Lithology: gabbro; diorite; ultramafic intrusive rock

Fine-grained granite (Jurassic) at surface, covers < 0.1 % of this area

Fine-grained granite - Commonly contains alkalic amphibole and mesoperthite.

Lithology: granite

Gabbro and diabase (Middle Ordovician) at surface, covers 0.5 % of this area

Gabbro and diabase - Foliated to nonfoliated and coarse- to fine-grained; includes mafic dikes tentatively correlated with Chickwolnepy intrusions.

Lithology: gabbro; diabase

Dead River Formation, Graded-bedded metapelite (Upper Cambrian? - Lower Ordovician?) at surface, covers 0.8 % of this area

Dead River Formation, Graded-bedded metapelite - Found in Percy quadrangle of northern New Hampshire.

Lithology: meta-argillite

Porphyritic (alkalic feldspar) biotite granite (Late Ordovician) at surface, covers 0.8 % of this area

Porphyritic (alkalic feldspar) biotite granite.

Lithology: granite

Granite porphyry (Early Jurassic) at surface, covers 0.4 % of this area

Granite porphyry - Granite containing phenocrysts of smoky quartz and microperthite; alkalic amphibole, hornblende, and hedenbergite or fayalite may be present. "Mount Lafayette" type granite porphyry of Billings (1955).

Lithology: granite

Ammonoosuc Volcanics, Volcaniclastic metagraywackes (Middle - Upper Ordovician) at surface, covers 0.3 % of this area

Ammonoosuc Volcanics, Volcaniclastic metagraywackes.

Lithology: metasedimentary rock

Mount Osceola Granite, Granite containing hornblende and, locally, hastingsite, ferrohedenbergite, or fayalite (Early - Middle Jurassic) at surface, covers 0.4 % of this area

Mount Osceola Granite, Granite containing hornblende and, locally, hastingsite, ferrohedenbergite, or fayalite.

Lithology: granite

Conway Granite (Middle - Late? Jurassic) at surface, covers 4 % of this area

Conway Granite - Typically pink, coarse-grained mesoperthitic biotite (amphibole-free) granite; locally fine-grained or porphyritic.

Lithology: granite

Ordovician - Cambrian unnamed volcanic rocks (Ordovician - Cambrian) at surface, covers < 0.1 % of this area

Ordovician - Cambrian unnamed volcanic rocks

Lithology: mafic volcanic rock; felsic volcanic rock

Perry Mountain Formation, undivided (Lower? - Middle? Silurian) at surface, covers 0.5 % of this area

Perry Mountain Formation, undivided - Sharply interbedded quartzites, light-gray nongraphitic metapelite, and "fast-graded" meta-turbidites. Coticule layers common.

Lithology: quartzite; meta-argillite; metasedimentary rock

Ammonoosuc Volcanics, White quartz-kyanite rock and silicate iron-formation (Middle - Upper Ordovician) at surface, covers < 0.1 % of this area

Ammonoosuc Volcanics, White quartz-kyanite rock and silicate iron-formation.

Lithology: schist; iron formation

Biotite granite (Middle Ordovician) at surface, covers 0.3 % of this area

Biotite granite - Contains minor muscovite. Makes up Cambridge Black pluton.

Lithology: granite

Ironbound Mountain Formation, Metarhyolite and microgranite intrusions (Lower Devonian) at surface, covers < 0.1 % of this area

Ironbound Mountain Formation, Metarhyolite and microgranite intrusions.

Lithology: meta-rhyolite; granite

Undifferentiated Granitic Rocks (Ordovician) at surface, covers < 0.1 % of this area

Undifferentiated granitic rocks.

Lithology: granite

Littleton Formation, Metaconglomerate and quartzite (Lower Devonian) at surface, covers < 0.1 % of this area

Littleton Formation, Metaconglomerate and quartzite - Locally fossiliferous in Whitefield quadrangle.

Lithology: meta-conglomerate; quartzite

Two-mica granite (Devonian - Mississippian) at surface, covers 4 % of this area

Two-mica granite - Found in northern New Hampshire.

Lithology: granite

Frontenac Formation, Proximal bimodal volcanic facies (Silurian?) at surface, covers 2 % of this area

Frontenac Formation, Proximal bimodal volcanic facies.

Lithology: metavolcanic rock

Ironbound Mountain Formation, Euxinic metashale member (Lower Devonian) at surface, covers < 0.1 % of this area

Ironbound Mountain Formation, Euxinic metashale member.

Lithology: metasedimentary rock

Smalls Falls Formation, Felsic metavolcanic member (Upper to Middle Silurian (Ludlovian and Wenlockian)) at surface, covers < 0.1 % of this area

Smalls Falls Formation, Felsic metavolcanic member.

Lithology: felsic metavolcanic rock

Dead River Formation, undivided (Upper Cambrian? - Lower Ordovician?) at surface, covers 8 % of this area

Dead River Formation, undivided - Thinly laminated, "pin-striped" gray, green, or tan metapelite and quartzite.

Lithology: meta-argillite; quartzite

Silurian - Ordovician Frontenac Formation (Silurian - Ordovician) at surface, covers < 0.1 % of this area

Silurian - Ordovician Frontenac Formation

Lithology: graywacke; slate

Silurian granite (Silurian) at surface, covers < 0.1 % of this area

Silurian granite

Lithology: granite

Perry Mountain Formation, Volcanic facies in Piermont allochthon (Lower? - Middle? Silurian) at surface, covers < 0.1 % of this area

Perry Mountain Formation, Volcanic facies in Piermont allochthon.

Lithology: felsic volcanic rock; mafic volcanic rock

Ammonoosuc Volcanics, Metasedimentary rocks (Middle - Upper Ordovician) at surface, covers < 0.1 % of this area

Ammonoosuc Volcanics, Metasedimentary rocks.

Lithology: metasedimentary rock

Hurricane Mountain Formation (Upper Cambrian?) at surface, covers 0.2 % of this area

Hurricane Mountain Formation - Rusty-weathered, dark siliceous scaly slate or schist of flaser structure, polymictic fragments from a few mm to (in Maine) several hundred meters. A melange consisting of metasedimentary, felsic/mafic metavolcanics, and ultramafic rocks..

Lithology: slate; schist; metasedimentary rock; metavolcanic rock; ultramafic intrusive rock

Smalls Falls Formation, Metaconglomerate member (Upper to Middle Silurian (Ludlovian and Wenlockian)) at surface, covers < 0.1 % of this area

Smalls Falls Formation, Metaconglomerate member - Found in Errol quadrangle in northern New Hampshire.

Lithology: meta-conglomerate

Madrid and Smalls Falls Formations, undivided (Silurian) at surface, covers 0.9 % of this area

Madrid and Smalls Falls Formations, undivided.

Lithology: granofels; schist; calc-silicate schist; pelitic schist

Hornblende-biotite quartz monzodiorite (Jurassic) at surface, covers 0.5 % of this area

Hornblende-biotite quartz monzodiorite - Composition ranges from quartz monzonite to diorite.

Lithology: quartz monzodiorite; quartz monzonite; diorite

Porphyritic hornblende diorite (Jurassic) at surface, covers 0.2 % of this area

Porphyritic hornblende diorite - Found in northwestern New Hampshire.

Lithology: diorite

Mesoperthitic granite (Jurassic) at surface, covers 0.7 % of this area

Mesoperthitic granite - Contains riebeckite and (or) hastingsite.

Lithology: granite

Ammonoosuc Volcanics, Bimodal volcanic rocks (Middle - Upper Ordovician) at surface, covers 1 % of this area

Ammonoosuc Volcanics, Bimodal volcanic rocks - Locally includes unmapped Oals.

Lithology: bimodal suite

Smalls Falls Formation, Mixed metavolcanic rocks and metavolcanic sediments (Upper to Middle Silurian (Ludlovian and Wenlockian)) at surface, covers 0.1 % of this area

Smalls Falls Formation, Mixed metavolcanic rocks and metavolcanic sediments.

Lithology: metavolcanic rock

Ironbound Mountain Formation, undivided (Lower Devonian) at surface, covers 3 % of this area

Ironbound Mountain Formation, undivided - Interbedded gray phyllite, in places containing feldspathic clasts, and feldspathic metasandstone, variably graded.

Lithology: phyllite; metasedimentary rock

Mount Osceola Granite, Green biotite mesoperthitic granite (Early - Middle Jurassic) at surface, covers < 0.1 % of this area

Mount Osceola Granite, Green biotite mesoperthitic granite.

Lithology: granite

Frontenac Formation, undivided (Silurian?) at surface, covers 13 % of this area

Frontenac Formation, undivided - Interbedded thick feldspathic wackes, tan and green slates, and minor calcareous lenses.

Lithology: metasedimentary rock; slate

Gile Mountain Formation, Hall Stream Member (Devonian) at surface, covers < 0.1 % of this area

Gile Mountain Formation, Hall Stream Member - Highly feldspathic grit, probably volcanic; feldspathic chlorite-ankerite schist and amphibolite; all northeast of Nulhegan River.

Lithology: schist; amphibolite

Biotite granite stock and dikes (Early - Late Silurian) at surface, covers 0.5 % of this area

Biotite granite stock and dikes - Northernmost New Hampshire.

Lithology: granite

Littleton Formation, undivided (Lower Devonian; Siegenian) at surface, covers 4 % of this area

Littleton Formation undivided - Gray metapelite and metawacke and subordinate metavolcanic rocks; generally, but not everywhere, conformable with underlying Fitch or Madrid Formations. Fossiliferous in western New Hampshire.

Lithology: metasedimentary rock; metavolcanic rock

Frontenac Formation, Metabasalt interbeds (Silurian?) at surface, covers 2 % of this area

Metabasalt interbeds.

Lithology: meta-basalt

Devonian quartz monzodiorite - quartz diorite (pyroxene plus hornblende accessory mineral) (Devonian) at surface, covers < 0.1 % of this area

Devonian quartz monzodiorite - quartz diorite (pyroxene plus hornblende accessory mineral) - Devonian pyroxene-hornblende quartz monzodiorite and quartz diorite - pyroxene-hornblende-biotite quartz monzodiorite, and pyroxene-hornblende-biotite quartz diorite

Lithology: quartz monzodiorite; quartz diorite

Ammonoosuc Volcanics, Metabasalt (Middle - Upper Ordovician) at surface, covers 2 % of this area

Ammonoosuc Volcanics, Metabasalt.

Lithology: meta-basalt

Frontenac Formation, Mixed volcanic and sedimentary facies (Silurian?) at surface, covers 0.5 % of this area

Frontenac Formation, Mixed volcanic and sedimentary facies.

Lithology: metavolcanic rock; metasedimentary rock

Hornblende or alkalic amphibole quartz syenite (Jurassic) at surface, covers 0.4 % of this area

Hornblende or alkalic amphibole quartz syenite.

Lithology: quartz syenite

Leucocratic granite to quartz syenite (Jurassic) at surface, covers 0.2 % of this area

Leucocratic granite to quartz syenite.

Lithology: granite; quartz syenite

Rangeley Formation, undivided (Lower Silurian (Llandoverian)) at surface, covers 5 % of this area

Rangeley Formation, undivided.

Lithology: metasedimentary rock; calc-silicate rock; meta-argillite; quartzite; pelitic schist; granofels; felsic metavolcanic rock

Hornblende-biotite granite (Late Ordovician) at surface, covers 2 % of this area

Hornblende-biotite granite.

Lithology: granite

Smalls Falls Formation, undivided (Upper to Middle Silurian (Ludlovian and Wenlockian)) at surface, covers 3 % of this area

Smalls Falls Formation, undivided -Very rusty weathering, thinly bedded sulfidic-graphitic schist and pyrrhotitic calc-silicate granofels. Eastern facies equivalent to lower part of the Fitch Formation. Locally mapped as Francestown Formation of Nielson (1981) in southern New Hampshire.

Lithology: schist; granofels

Ordovician unnamed volcanic and sedimentary rocks (Ordovician) at surface, covers < 0.1 % of this area

Ordovician unnamed volcanic and sedimentary rocks

Lithology: mafic volcanic rock; felsic volcanic rock; sedimentary rock

Biotite granite (Late Ordovician) at surface, covers 6 % of this area

Biotite granite - Pink, moderately to weakly foliated.

Lithology: granite

Hastingsite granite (Jurassic) at surface, covers < 0.1 % of this area

Hastingsite granite - Leucocratic, pink or light-brown, and mesoperthitic.

Lithology: granite

Two-mica granite of northern and southeastern New Hampshire (Early - Late Devonian) at surface, covers 3 % of this area

Two-mica granite of northern and southeastern New Hampshire - Similar to Concord Granite.

Lithology: granite

Member C (uppermost) of the Rangeley Formation in Maine and northeastern and southwestern New Hampshire (Lower Silurian (Llandoverian)) at surface, covers 0.4 % of this area

Member C (uppermost) of the Rangeley Formation in Maine and northeastern and southwestern New Hampshire - Quartz-pebble conglomerate overlain by rusty metapelite and feldspathic quartzite.

Lithology: conglomerate; meta-argillite; quartzite

Hornblende-biotite tonalite (Middle Ordovician) at surface, covers < 0.1 % of this area

Hornblende-biotite tonalite.

Lithology: tonalite

Gabbro (Jurassic) at surface, covers < 0.1 % of this area

Gabbro - Has varying amounts of olivine, augite, and hornblende.

Lithology: gabbro

Biotite granodiorite (Late Ordovician) at surface, covers 1 % of this area

Biotite granodiorite.

Lithology: granodiorite

Ammonoosuc Volcanics, Felsic metavolcanic rocks (Middle - Upper Ordovician) at surface, covers 0.2 % of this area

Ammonoosuc Volcanics, Felsic metavolcanic rocks.

Lithology: felsic metavolcanic rock

Hornblende granite to granodiorite (Late Ordovician) at surface, covers 0.6 % of this area

Hornblende granite to granodiorite - Part of Lost Nation pluton of northwestern New Hampshire.

Lithology: granite; granodiorite

Perry Mountain and Rangeley Formations, undivided (Silurian) at surface, covers < 0.1 % of this area

Perry Mountain and Rangeley Formations, undivided.

Lithology: quartzite; calc-silicate rock; felsic metavolcanic rock; meta-argillite; granofels; metasedimentary rock; conglomerate; pelitic schist

Ordovician - Cambrian Aziscohos Formation (Ordovician - Cambrian) at surface, covers < 0.1 % of this area

Ordovician - Cambrian Aziscohos Formation

Lithology: shale; quartzite; siltstone

Jim Pond Formation (Upper Cambrian) at surface, covers < 0.1 % of this area

Jim Pond Formation - Pillow metabasalt member. Lenses within the Hurricane Mountain Formation of northern New Hampshire interpreted as tectonic rafts of Jim Pond Formation.

Lithology: meta-basalt

Two-mica granite of the Sebago batholith and Effingham pluton of eastern New Hampshire (Mississippian - Pennsylvanian) at surface, covers < 0.1 % of this area

Two-mica granite of the Sebago batholith and Effingham pluton of eastern New Hampshire.

Lithology: granite

Devonian granite (muscovite accessory mineral) (Devonian) at surface, covers < 0.1 % of this area

Devonian granite (muscovite accessory mineral); muscovite-biotite granite

Lithology: granite

Ordovician - Cambrian Dead River formation (Ordovician - Cambrian) at surface, covers < 0.1 % of this area

Ordovician - Cambrian Dead River formation

Lithology: slate; quartzite; phyllite

Syenite (Permian-Triassic) at surface, covers < 0.1 % of this area

Syenite - Hornblende, biotite, quartz and augite syenites.

Lithology: syenite; quartz syenite

Ironbound Mountain Formation, Basaltic to andesitic member (Lower Devonian) at surface, covers < 0.1 % of this area

Ironbound Mountain Formation, Basaltic to andesitic member.

Lithology: basalt; andesite

Aziscohos Formation, Lower unnamed member (Upper Cambrian? - Lower Ordovician?) at surface, covers 0.9 % of this area

Aziscohos Formation, Lower unnamed member - Rusty, dark metapelite containing thin coticule laminations, feldspathic metatuff, and vein quartz lenses.

Lithology: meta-argillite; metavolcanic rock

Porphyritic phase of hornblende-biotite tonalite (Middle Ordovician) at surface, covers 0.2 % of this area

Porphyritic phase of hornblende-biotite tonalite.

Lithology: tonalite

Biotite quartz diorite in northeastern New Hampshire (Early - Late Devonian) at surface, covers 0.9 % of this area

Biotite quartz diorite in northeastern New Hampshire

Lithology: quartz diorite

Cambrian Jim Pond Formation graywacke (Cambrian) at surface, covers < 0.1 % of this area

Cambrian Jim Pond Formation graywacke

Lithology: graywacke

Kinsman Granodiorite (Early Devonian ) at surface, covers 0.1 % of this area

Kinsman Granodiorite - (Kinsman Quartz Monzonite of Billings, 1955) - Foliated granite, granodiorite, tonalite, and minor quartz diorite; large megacrysts of potassium feldspar characteristic; garnet locally abundant.

Lithology: granite; granodiorite; tonalite; quartz diorite

Undifferentiated Granitic Gneiss (Devonian) at surface, covers < 0.1 % of this area

Undifferentiated Granitic Gneiss - Small dikes and sills do not show.

Lithology: granitic gneiss

Smalls Falls Formation, Metabasalt member (Upper to Middle Silurian (Ludlovian and Wenlockian)) at surface, covers 0.9 % of this area

Smalls Falls Formation, Metabasalt member.

Lithology: meta-basalt

Porphyritic biotite granodiorite in northern Jefferson dome in Milan quadrangle (Late Ordovician ) at surface, covers 0.6 % of this area

Porphyritic biotite granodiorite in northern Jefferson dome in Milan quadrangle.

Lithology: granodiorite

Littleton Formation, Volcanic lentils (Lower Devonian) at surface, covers < 0.1 % of this area

Littleton Formation, Volcanic lentils - Both mafic and felsic

Lithology: mafic metavolcanic rock; felsic metavolcanic rock

Gile Mountain Formation, undivided (Lower Devonian) at surface, covers 0.3 % of this area

Gile Mountain Formation, undivided - Gray to tan metawacke and schist or phyllite; gradational into Meetinghouse Slate Member but more thickly bedded and less pelitic than the member. Includes minor metavolcanic lentils.

Lithology: schist; metasedimentary rock; phyllite; slate; metavolcanic rock

Metamorphosed gabbro, diorite, and intrusive basalt dikes (Devonian? - Silurian?) at surface, covers 0.2 % of this area

Metamorphosed gabbro, diorite, and intrusive basalt dikes - Chiefly in northern New Hampshire.

Lithology: metavolcanic rock

Madrid Formation (Upper Silurian? ) at surface, covers 0.6 % of this area

Madrid Formation - Massive to weakly foliated, purple biotite-feldspar granofels, layered calc-silicate, and dark pelitic-sulfidic schist containing calc-silicate pods in upper member; an eastern facies equivalent to the upper part of the Fitch Formation. Locally mapped as the Warner Formation of Nielson (1981) in southern New Hampshire.

Lithology: granofels; calc-silicate schist; pelitic schist

Hornblende (or alkalic amphibole) syenite (Jurassic) at surface, covers 2 % of this area

Hornblende (or alkalic amphibole) syenite.

Lithology: syenite

Cambrian Hurricane Mountain Formation (Cambrian) at surface, covers < 0.1 % of this area

Cambrian Hurricane Mountain Formation

Lithology: melange

Albee Formation (Ordovician) at surface, covers < 0.1 % of this area

Albee Formation - Massive, gray, white-weathered quartzite and feldspathic quartzite interbedded with greenish-gray slate, phyllite, feldspthic phyllite and quartzose argillaceous phyllite. Micaceous quartzite, quartz-mica schist, mica schist and hornfels contining porphyroblasts of biotite, garnet, staurolite and sillimanite in the vicinity of granitic plutons. Soda-rhyolite tuff occurs locally. Micaceous quartzite characterized by thin, schistose "pinstripe" partings is common in many areas.

Lithology: quartzite; slate; phyllite; mica schist; hornfels; tuff

Porphyritic biotite quartz syenite in central Jefferson dome in Mt. Washington quadrangle (Late Ordovician) at surface, covers 0.2 % of this area

Porphyritic biotite quartz syenite in central Jefferson dome in Mt. Washington quadrangle.

Lithology: quartz syenite

Ordovician - Cambrian Dead River formation lower member (Ordovician - Cambrian) at surface, covers < 0.1 % of this area

Ordovician - Cambrian Dead River formation lower member

Lithology: quartzite; phyllite

Hornblende quartz monzonite (Late Ordovician) at surface, covers 0.6 % of this area

Hornblende quartz monzonite.

Lithology: quartz monzonite

Gile Mountain Formation (Devonian) at surface, covers 0.1 % of this area

Gile Mountain Formation - Gray quartz-muscovite phyllite or schist, interbedded and intergradational with gray micaceous quartzite (graywacke northeast of Nulhegan River), calcareous mica schist, and, locally, quartzose and micaceous crystalline limestone like that of the Waits River formation. The phyllite and schist commonly contain porphyroblasts of biotite, garnet, or staurolite, and locally kyanite, andalusite, or sillimanite. Used as Early Devonian Gile Mountain Formation. Generally consists of gray to tan metawacke and schist or phyllite, gradational into its Meetinghouse Slate Member, but much more thickly bedded and less pelitic. Contains minor metavolcanic lentils. Unnamed metavolcanic member is possibly equivalent to Putney Volcanics of southeastern VT. Separately mapped interbedded gray slate or phyllite and brown-weathering calcite-ankerite metasiltstone, and minor marble and quartzite, resembles Waits River Formation of VT. Meetinghouse Slate Member consists of gray to black phyllite and silty metasandstone turbidite. Report includes geologic map, cross sections, correlation chart, and four 1:500,000-scale derivative maps (Lyons and others, 1997).

Lithology: phyllite; mica schist; quartzite; limestone; graywacke

Perry Mountain Formation, Sedimentary and subordinate distal felsic and mafic volcanic facies in Piermont allochthon (Lower?- Middle? Silurian) at surface, covers 7 % of this area

Perry Mountain Formation, Sedimentary and subordinate distal felsic and mafic volcanic facies in Piermont allochthon.

Lithology: metasedimentary rock; felsic metavolcanic rock; mafic metavolcanic rock

Frontenac Formation, Graded-bedded metagraywacke and subordinate gray phyllite (Silurian?) at surface, covers 0.3 % of this area

Frontenac Formation, Graded-bedded metagraywacke and subordinate gray phyllite.

Lithology: metasedimentary rock; phyllite

Devonian Ironbound Mountain Formation (Devonian) at surface, covers < 0.1 % of this area

Devonian Ironbound Mountain Formation

Lithology: slate

Pink equigranular biotite granite (Late Devonian) at surface, covers 0.3 % of this area

Pink equigranular biotite granite - Found in Woodsville and Whitefield quadrangles and in small intrusive units in northern and southeastern New Hampshire.

Lithology: granite

Trondhjemite and quartz diorite in northern Jefferson dome in Gorham quadrangle (Late Ordovician) at surface, covers 2 % of this area

Trondhjemite and quartz diorite in northern Jefferson dome in Gorham quadrangle.

Lithology: trondhjemite; quartz diorite

Ironbound Mountain Formation, Grits at Halls Stream in northern New Hampshire (Lower Devonian) at surface, covers 0.3 % of this area

Ironbound Mountain Formation, Grits at Halls Stream in northern New Hampshire - Thickly bedded feldspathic volcaniclastic grit and interbedded gray slate. Equivalent to Grenier Ponds Member of the Ironbound Mountain Formation in western Maine.

Lithology: metavolcanic rock; slate

Frontenac Formation, Massive tan- or brown-weathering calcite-ankerite-muscovite granofels and interbedded gray metapelite (Silurian?) at surface, covers 1 % of this area

Frontenac Formation, Massive tan- or brown-weathering calcite-ankerite-muscovite granofels and interbedded gray metapelite - Probably partly a facies equivalent to the Waits River Formation in Vermont.

Lithology: granofels; meta-argillite

Hornblende-biotite quartz syenite to syenite (Late Ordovician) at surface, covers 2 % of this area

Hornblende-biotite quartz syenite to syenite.

Lithology: quartz syenite; syenite

Ironbound Mountain Formation, Felsic volcanic member (Lower Devonian) at surface, covers 0.9 % of this area

Ironbound Mountain Formation, Felsic volcanic member.

Lithology: felsic volcanic rock

Migmatitic rocks (Devonian - Silurian) at surface, covers 1 % of this area

Migmatitic rocks - Formations unidentifiable owing to obliteration of original sedimentary or volcanic characteristics by anatexis or by numerous intrusions.

Lithology: migmatite

Aziscohos Formation, Upper unnamed member (Upper Cambrian? - Lower Ordovician?) at surface, covers 0.5 % of this area

Aziscohos Formation, Upper unnamed member - Gray metapelite containing sparse siltstone laminations and abundant lenses of vein quartz.

Lithology: meta-argillite; siltstone

Tonalite, diorite, granodiorite, and granite (Late Ordovician ) at surface, covers 2 % of this area

Tonalite, diorite, granodiorite, and granite - More mafic rocks have hornblende; part of Lost Nation pluton.

Lithology: tonalite; diorite; granodiorite; granite

Metavolcanic and metasedimentary rocks of the lower part of Ammonoosuc Volcanics, undivided (Middle Ordovician) at surface, covers 2 % of this area

Metavolcanic and metasedimentary rocks of the lower part of Ammonoosuc Volcanics, undivided.

Lithology: metavolcanic rock; metasedimentary rock