Dark-gray to silvery-gray, lustrous, carbonaceous muscovite-biotite-quartz (±garnet) phyllite containing abundant beds of punky-brown-weathering, dark-bluish-gray micaceous quartz-rich limestone in beds ranging from 10 cm to 10 m thick. Part of the Connecticut Valley Trough.
Gray to light-gray, fine-grained micaceous quartzite a few centimeters to tens of centimeters thick, interbedded with dark-gray graphitic slate, phyllite, or schist. Part of the Connecticut Valley Trough.
Schist, gneiss, and quartzite; dark-rusty-brown graphitic biotite-muscovite-chlorite-quartz (±garnet) schist and gneiss; black albite porphyroblasts, large euhedral pyrite, and beds of dark-gray foliated quartzite are common. Unit includes rusty-weathering schist without graphite and rocks identical to Fayston Formation. Cover rocks north of the Lincoln Mountain massif.
Interlayered grayish-green and rusty-weathering black quartzose phyllite, similar to dark carbonaceous phyllites of the Ottauquechee Formation (Co). Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Gray- to bluish-gray, fine- to medium-grained, thinly bedded calcareous metasandstone, quartzose metalimestone, and fissile, laminated calcareous metasandstone and phyllite. Part of the Connecticut Valley Trough.
Light-gray to pink, medium- to coarse-grained, massive, seriate to porphyritic granodiorite and granite. Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Light-gray to pink, medium- to very coarse grained, massive, miarolitic garnet-muscovite peraluminous leucogranite. Pegmatitic main zone. Rb/Sr whole-rock age of 376±9 Ma (Ayuso and Arth, 1992). Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Predominantly dark-gray to black, carbonaceous to highly graphitic, fine-grained sulfidic biotite-muscovite-quartz phyllite having silicic laminae. Includes black quartzites not mapped separately. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Light-gray to tan, fine-grained albite-chlorite-sericite-quartz phyllitic quartzite interlayered with light-greenish-gray quartzofeldspathic granofels and dark-gray phyllite. Contains numerous boudinaged, massive to foliated, dark-green metamorphosed mafic dikes and sills. Part of the metasedimentary host rocks of the North River Igneous Suite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Light-gray to pale-green, whitish-gray-weathering, chlorite-biotite-plagioclase-quartz granofels and tectonically “pinstriped” granofels and feldspathic biotite quartzite. Part of the metasedimentary host rocks of the North River Igneous Suite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Binary and biotite granite and granodiorite, undifferentiated. Includes small dikes labeled Dg. Part of the New Hampshire Plutonic Suite.
Light-gray, medium- to coarse-grained, massive, epidote-biotite-muscovite porphyritic granodiorite and minor tonalite. Rb/Sr whole-rock isochron age of 370±17 Ma (Ayuso and Arth, 1992). Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Gray to pink, medium- to coarse-grained garnet-muscovite-biotite granite and pegmatite, undifferentiated. Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Part of unit CZs local areas rich in metadiabase dikes. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Tan to light-bluish-gray, brown-weathering, medium- to coarse-grained, equigranular to porphyritic foliated granodiorite composed of quartz, plagioclase, perthite, microcline, biotite, and sericite. Part of the Lake Memphremagog Intrusive Suite (425±3 Ma to 418.5±2 Ma).
White, light-gray- and green-banded, medium-grained, well-layered epidote-white mica-quartz-albite (±garnet±magnetite) gneiss with plagioclase and polycrystalline quartz porphyroblasts. Green, chloritic layers 2 to 10 cm thick also contain chlorite pseudomorphs after garnet. Gneiss is similar to gneiss at the base of the Belvidere Mountain Structural Complex. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Predominantly dark-gray to grayish-green quartz-chlorite-(biotite)-muscovite phyllite; contains 1- to 2-cm-thick beds of dark-gray metasiltstone and quartzite, and thicker beds of dark-bluish-gray vitreous quartzite, grayish-green to light-yellowish-green sericite phyllite (felsic tuffs) and cobble to boulder conglomerate, and greenstone. Mapped north of the Braintree Intrusive Complex and near Brattleboro. Part of the metasedimentary host rocks of the North River Igneous Suite. Cram Hill Formation: western part of the Cram Hill Formation is in part correlative with Whetstone Hill Member of the Moretown Formation. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Dark-gray to silvery-gray, lustrous, fine-grained carbonaceous quartz-muscovite phyllite and silicic phyllite, and garnet-rich biotite-muscovite-quartz schist; contains millimeter- to centimeter-thick beds of gray quartzite and metasiltstone, and thicker beds of quartz-feldspar grit or quartzite near base. Transition zone into Waits River Formation west of the Guilford dome consists of as much as 5 percent beds of punky limestone. Part of the Connecticut Valley Trough.
Light-gray to pink, medium- to very coarse grained, massive, miarolitic garnet-muscovite peraluminous leucogranite. Biotitic granodioritic western zone. Rb/Sr whole-rock age of 376±9 Ma (Ayuso and Arth, 1992). Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Dark-gray, carbonaceous garnet-pyrite-sericite-chlorite-quartz phyllite with clasts of siltstone, phyllite, quartzite, and dark-gray slate breccia interbedded with Coburn Hill Metabasalt Member (Ochcv). Unit correlative with the St. Daniel Group of Québec. Part of the Cram Hill Formation of the Newport Center area. Part of the metasedimentary host rocks of the North River Igneous Suite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Brown to white-weathering, green, massive, moderately to fully serpentinized dunite and peridotite and schistose serpentinite; rusty-weathering, medium-grained talc-carbonate rock and quartz-carbonate (magnesite) rock. Part of Ultramafic rocks: occur as tectonic slivers and olistoliths in blocks within the Hazens Notch, Ottauquechee, Stowe, Rowe, and Moretown Formations. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Occurs at different stratigraphic levels. Includes dark-gray and white layered metadacite and meta-andesite, gray- to tan-weathering blue-quartz phenocrystic metadacitic agglomerate, and grayish-green fragmental metadacitic and meta-andesite breccia. Similar to the volcanic agglomerate (Omwhv) within the Whetstone Hill Member of the Moretown Formation. A similar felsic layer interlayered within the Cram Hill Formation has a U-Pb zircon SHRIMP age of 483±3 Ma, no. 25 (Aleinikoff and others, 2011). Part of the metasedimentary host rocks of the North River Igneous Suite. Cram Hill Formation: western part of the Cram Hill Formation is in part correlative with Whetstone Hill Member of the Moretown Formation. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Light-gray to tan, rusty-weathering, fine- grained quartz-sericite-chlorite-albite phyllite, quartzite, and flinty sulfidic granofels; thin layers of felsite, conglomerate, and breccia occur in the vicinity of Coburn Hill. Paper schist fabric occurs locally on the west side of Coburn Hill. Part of the Cram Hill Formation of the Newport Center area. Part of the metasedimentary host rocks of the North River Igneous Suite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Light-grayish-green, fine-grained, chlorite-muscovite-quartz phyllite or schist and quartzite; white quartzofeldspathic layers alternate with green chloritic phyllitic layers; locally albitic. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Tan to gray phyllitic metawacke composed of rounded to angular grains of quartz, blue quartz, albite, and traces of detrital rock fragments in a fine-grained matrix of quartz, sericite, and chlorite. Feldspathic metawacke is common; quartz grains range in size from 0.5 mm to 0.5 cm. Conglomerate and breccia occur locally at The Knob (northwest of Lake Eden) and just north of the Lowell-Westfield town line. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Outer zone of quartz gabbro and quartz diorite. Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Mafic schist and amphibolite unit. Dark-bluish-gray, fine- to medium-grained, massive to foliated blueschist composed of amphibole (glaucophane, barroisite, and actinolite), epidote, garnet, chlorite with minor magnetite, pyrite, and apatite. Quartz and garnet coticule occur locally. Eclogite occurs locally, delimited by green, medium-grained layers and pods of garnet, omphacite, glaucophane, epidote, quartz, albite, and white mica. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Light-gray to tan, rusty-weathering, laminated sandy muscovite-plagioclase-quartz schist and tan quartzite. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Quartz-pebble and phyllitic-fragment conglomerate, and tan to gray phyllite. Occurs as lenses, locally unconformable with the underlying Stowe Formation at Umbrella Hill; occurs at different stratigraphic levels in the Cram Hill Formation north of Albany. Interbedded with Coburn Hill Metabasalt Member (Ochcv) and phyllite-chip conglomerate and slate conglomerate member (Ochsb) north of Albany. Part of the Cram Hill Formation of the Newport Center area. Part of the metasedimentary host rocks of the North River Igneous Suite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Gray to silvery-green, sericite-chlorite-quartz phyllite with thin beds of rusty-weathering, pearly-white, fine-grained granofels. Interlayered with Ochuc and Ochsb at the contacts. Mapped locally in the Albany area. Part of the Cram Hill Formation of the Newport Center area. Part of the metasedimentary host rocks of the North River Igneous Suite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Metamorphosed diorite, trondhjemite, and diabase, consisting of massive to foliated, light-gray to grayish-green, chalky-weathering diorite with xenoliths of green phyllite and trondhjemite; and massive, tan-weathering, medium- to coarse-grained trondhjemite with xenoliths of diabase. Numerous crosscutting quartz-feldspar veinlets show in relief on the weathering surface. Unit intrudes Cram Hill Formation. U-Pb zircon SHRIMP age of 425±3 Ma, no. 39 (Aleinikoff and others, 2011). Part of the Lake Memphremagog Intrusive Suite (425±3 Ma to 418.5±2 Ma).
Silvery-green to grayish-green, medium-grained albite-chlorite-muscovite-quartz (±garnet±magnetite) schist with white albite porphyroblasts; resembles albitic schists of the Tyson Formation (CZtab) and green albitic granofels of the Hoosac Formation (CZhgab). Locally contains unmapped light-gray, thin quartzites; salt-and-pepper-colored, medium- to coarse-grained pyrite-magnetite-biotite-albite-quartz schist and gneiss; and silvery-dark-gray to rusty-weathering, medium-grained chlorite-tourmaline-albite-muscovite-quartz schist. The Fayston south of Mount Abraham is interca-lated with rocks of the Tyson Formation and with the schists of the Pinney Hollow Formation. Cover rocks north of the Lincoln Mountain massif.
Rusty-grayish-brown-weathering, locally splintery-fractured, dark-gray to steel-gray biotite-quartz-feldspathic schist and quartzite and interbedded carbonaceous, small-garnet papery muscovite phyllite and schist similar to Ochs. Part of the metasedimentary host rocks of the North River Igneous Suite. Cram Hill Formation: western part of the Cram Hill Formation is in part correlative with Whetstone Hill Member of the Moretown Formation. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Rim zone of granodiorite of unit Ddbg. Rb/Sr whole-rock isochron age of 370±17 Ma (Ayuso and Arth, 1992). Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Dark-green plagioclase-hornblende (±quartz) amphibolite and rusty-pale-green, punky-weathering ankeritic-chloritic greenstone. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Inner zone of granite. Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Dark-gray, medium- to coarse-grained, massive, quartz-biotite-hornblende (±pyroxene) gabbro and diorite. Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Interbedded feldspathic quartzite within unit CZsa. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
White to yellowish-gray quartz-pebble conglomerate and conglomeratic quartzite, having clasts of milky-white quartz as much as 2.5 cm in diameter in a white to tan quartzite matrix, in beds 0.5 to 1 m thick; and yellowish-gray to light-gray phyllitic quartzite, quartz-pebble to -granule phyllite, and steel-gray to tan vitreous quartzite in beds as much as 5 m thick. Part of the Connecticut Valley Trough.
Light-gray to pink, medium- to very coarse grained, massive, miarolitic garnet-muscovite peraluminous leucogranite. Inner hydrothermally altered zone. Rb/Sr whole-rock age of 376±9 Ma (Ayuso and Arth, 1992). Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
Light-gray to whitish-gray, fine-grained sericite-quartz-phenocrystic phyllitic metatuff and whitish pyritiferous soda-rhyolite metatuff. Abundant screens and layers occur within mafic rocks of the North River Igneous Suite and at scattered localities north of the Braintree intrusive complex and in the Coburn Hill area. Part of the metasedimentary host rocks of the North River Igneous Suite. Cram Hill Formation: western part of the Cram Hill Formation is in part correlative with Whetstone Hill Member of the Moretown Formation. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Light-green, fine- to medium-grained, massive carbonate-biotite-quartz-sphene-chlorite-actinolite-epidote greenstone with deformed pillows; interfingers with the Umbrella Hill Conglomerate Member (Ochuc) and with phyllite-chip conglomerate (Ochsb). Part of the Cram Hill Formation of the Newport Center area. Part of the metasedimentary host rocks of the North River Igneous Suite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Brown to white-weathering, green, massive, moderately to fully serpentinized dunite and peridotite and schistose serpentinite; rusty-weathering, medium-grained talc-carbonate rock and quartz-carbonate (magnesite) rock. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Light-grayish-brown- to tan-weathering, medium-dark-gray, fine-grained garnet (small)-biotite-muscovite phyllite and schist. Similar to phyllite facies (Omwh) in the Whetstone Hill Member of the Moretown Formation. Part of the metasedimentary host rocks of the North River Igneous Suite. Cram Hill Formation: western part of the Cram Hill Formation is in part correlative with Whetstone Hill Member of the Moretown Formation. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Predominantly fine-grained, lustrous, well-foliated, silvery-green, grayish-green, and bright-green, quartz-ribbed and -knotted, magnetite-chlorite (biotite)-albite (plagioclase)-sericite (muscovite)-quartz phyllite and schist. Locally richly garnetiferous and biotite-flecked schist (CZsgt) at higher grades. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.
Light- to medium-gray, fine-grained micaceous quartzite to dark-gray muscovite-quartz-biotite carbonaceous phyllite or schist in beds 10 to 25 cm thick; and dark-gray micaceous phyllite or schist containing beds of micaceous quartzite; locally thickly bedded. Detrital volcanic zircons yield a U-Pb age of 409±5 Ma, no. 51 (McWilliams and others, 2010). Part of the Connecticut Valley Trough.
Hornblende amphibolite and hornblende-plagioclase-quartz granofels; interpreted as metabasaltic and volcaniclastic rocks. Part of the Connecticut Valley Trough.
Cream-colored to light-bluish-gray, brown-weathering, talc-carbonate schist and talc-cabonate-rich rocks. Part of Ultramafic rocks: occur as tectonic slivers and olistoliths in blocks within the Hazens Notch, Ottauquechee, Stowe, Rowe, and Moretown Formations. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
White, light-gray- and green-banded, fine- to medium-grained, well-layered epidote-white mica-quartz-albite (±garnet±magnetite) gneiss; contains plagioclase and polycrystalline quartz porphyroblasts. The 0.5- to 2-cm-thick layers are defined by variations in the amount of quartz, albite, white mica, and chlorite. Gneiss is similar to gneiss at the base of the Tillotson Peak Structural Complex. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Dark-green, pitted-weathering, foliated mafic schist to massive greenstone containing varying amounts of chlorite, albite, carbonate, epidote, amphibole, and sphene; and amphibolite containing varying amounts of hornblende, actinolite, albite, chlorite, epidote, biotite, magnetite, and sphene. Cover rocks north of the Lincoln Mountain massif.
Dark-gray, coarse-grained amphibolite and layered amphibolite composed of barroisite, epidote, garnet, actinolite, albite, chlorite, sphene, sericite, biotite, and calcite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Gray- to bluish-gray polymict limestone metaconglomerate containing pebbles to cobbles of limestone, pelite, granite, and intermediate to felsic volcanic rocks; also locally occurs in the Northfield Formation. Part of the Connecticut Valley Trough.
Silvery-gray, medium-grained schist composed of white mica, quartz, chlorite (±garnet±albite±glaucophane±chloritoid); local centimeter-thick lenses of coticule. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Bluish-gray, fine- to medium-grained albite-horn-blende-epidote-actinolite (±garnet) amphibolite and quartz-bearing amphibolite. Rocks of the Early to Late Taconic Accreted Terrane of the Rowe-Hawley Zone. Eastern allochthonous sequence, oceanic and accretionary realm, ultramafic inclusions, volcanic-arc intrusives, and volcanic rocks.
Green, carbonate-albite-epidote-chlorite greenstone. Rocks of the Rowe-Hawley Zone. Allochthonous cover sequence east of the Green Mountains: rift and drift stage metasedimentary and metavolcanic rocks and tectonic inclusions of ultramafic rocks.