Lower contact grades downward through several meters feet of silty limestone to interbedded limestone and calcareous siltstone of the Schoharie Formation. Thickness is approximately 82 m ft. Onondaga Limestone Middle Devonian Vanuxem - Light-medium-gray- weathering, medium gray, fine-grained, thin- to thick-bedded fossiliferous limestone. Black chert more abundant in upper half of unit. Lower contact grades into interbedded limestone and calcareous siltstone of the Schoharie Formation.
Thickness approximately 60 m ft. Coeymans Formation, Kalkberg Limestone, Coeymans Limestone, Manlius Limestone, undivided - At New York border consists of fine-grained, chert-bearing, argillaceous limestone Kalkberg Limestone grading downward through coarse-grained limestone Coeymans Limestone into fine-grained limestone Manlius Limestone.
Toward southwest these units grade into fine- to coarse-grained limestone with a marked increase in quartz sand that comprises the Coeymans Formation Epstein and others, Total thickness 27 m 90 ft.
Coeymans Formation Epstein and others, - Medium-light-gray, fine- to coarse-grained calcareous sandstone and medium-gray, fine- to coarse-grained, medium- to thick-bedded, locally irregularly-bedded, argillaceous to arenaceous limestone containing lenses of quartz sand and nodules of black chert. Grades downward into medium-gray, fine-grained, argillaceous and arenaceous limestone containing local beds of fine- to coarse-grained pebbly calcareous sandstone. Local bioherms consisting of light-gray to light-pinkish-gray, coarse-grained to very coarse biogenic limestone are unbedded and have sharp boundaries.
Lower contact of unit abrupt. Formation thickness varies from 11 m 35 ft in northeast to 24 m 80 ft in southwest. Kalkberg Limestone Chadwick, - Medium-gray-weathering, medium-dark-gray, fine-grained, very thin to massively bedded fossiliferous limestone. Grades downward into fine- to medium-grained, thin-bedded, fossiliferous argillaceous limestone containing nodules and lenses of dark-gray chert. Grades to the southwest into calcareous and arenaceous rocks of the upper part of the Coeymans Formation near Wallpack Center.
Lower contact placed at base of lowest black chert. Approximately 12 m 40 ft thick. Coeymans Limestone Clarke and Schuchert, - Medium-gray weathering, medium-dark-gray, fine-to-coarse-grained, medium- to massively bedded fossiliferous limestone and local argillaceous limestone lenses. Unit is approximately 9 m 30 ft thick. Between Duttonville and Millville, grades into biohermal and nonbiohermal facies of medium- to coarse-grained limestone of Coeymans Formation of Epstein and others Manlius Limestone Vanuxem, - Medium-gray weathering, medium-dark- to dark-gray, very fine to fine-grained, unevenly bedded fossiliferous limestone.
Some local medium-grained limestone, yellowish-gray shale partings and biostromes. Near Hainesville, unit grades into lower part of Coeymans Formation. Lower contact abrupt and placed at top of uppermost very fine grained argillaceous limestone. Thickness approximately 11 m 35 ft. Green Pond Conglomerate Rogers, - Medium- to coarse-grained quartz-pebble conglomerate, quartzitic arkose and orthoquartzite, and thin- to thick-bedded reddish-brown siltstone.
Grades downward into gray, very dark-red, or grayish-purple, medium- to coarse-grained, thin- to very thick bedded pebble to cobble conglomerate containing clasts of red shale, siltstone, and chert; yellowish-gray sandstone and chert; dark-gray shale and chert; and white-gray and pink milky quartz. Quartz cobbles are as long as 10 cm 4 in. Milky quartz pebbles average 2.
Red arkosic quartz-pebble conglomerate and quartzite are more abundant than gray and grayish-green quartzite. About m ft thick. Jacksonburg Limestone and Sequence at Wantage, undivided - Jacksonburg Limestone - Upper part is medium- to dark-gray, laminated to thin-bedded shaly limestone and less abundant medium-gray arenaceous limestone containing quartz-sand lenses.
Upper part thin to absent to northeast. Lower part is interbedded medium- to dark-gray, fine- to medium-grained, very thin to medium-bedded fossiliferous limestone and minor medium- to thick-bedded dolomite-cobble conglomerate having a limestone matrix.
Unconformable on Beekmantown Group and conformable on the discontinuous sequence at Wantage in the Paulins Kill area. Contains conodonts of North American midcontinent province from Phragmodus undatus to Aphelognathus shatzeri zones of Sweet and Bergstrom Thickness ranges from 41 to m ft. Sequence at Wantage - Restricted, discontinuous sequence of interbedded limestone, dolomite, conglomerate, siltstone, and shale.
Upper part is medium-yellowish-brown- to olive-gray-weathering, medium- to dark-gray, very fine to fine-grained, laminated to massive limestone and dolomite that grade down into underlying clastic rocks of lower part. Upper part locally absent. Lower part ranges from grayish-red, medium-gray, pale-brown, and greenish-gray to pale-green mudstone and siltstone containing disseminated subangular to subrounded chert-gravel, quartz-sand lenses, and chert-pebble conglomerate.
Lower contact unconformable. Thickness ranges from 0 to 46 m ft. Minisink Limestone and New Scotland Formation, undivided - Minisink Limestone Epstein and others, - Light-medium-gray-weathering, medium-gray, fine-grained, medium-bedded, partly massive, argillaceous fossiliferous limestone.
Some nodules and lenses of purer limestone occur locally. Lower contact gradational. Thickness uniformly 7 m 23 ft. New Scotland Formation Clarke and Schuchert, - Upper part is dark-gray, very fine grained, laminated to thin-bedded siliceous shale containing pods of medium-dark-gray, very fine grained limestone; scattered thin beds and lenses of medium-gray, fine-grained argillaceous fossiliferous limestone; and small dark-gray chert nodules. Lower part is medium-dark-gray, thin-bedded, siliceous, fossiliferous calcareous shale.
Contains thin beds and lenses of medium-gray, fine-grained, highly fossiliferous, argillaceous limestone containing nodules, lenses and, locally, irregular beds of dark-gray chert.
Lower contact abrupt and placed at top of calcareous quartz sandstone. Total thickness is approximately 23 m 75 ft. Oriskany Group, undivided Willard, - Thickness ranges from 38 m ft in southwest to 52 m ft in northeast.
Ridgely Sandstone Swartz and others, - White-weathering, medium-gray, medium- to thick-bedded, carbonate-cemented quartz-pebble conglomerate and coarse quartz sandstone, which contain abundant brachiopods. Moderately well sorted, subrounded sand gains. Unit thins northeastward and pinches out at Peters Valley. Lower contact abrupt. Thickness ranges from 0 to 10 m ft. Shriver Chert Swartz and others, - Medium- to dark-gray-weathering, black to dark-gray, medium-to-thick-bedded siltstone and shale containing interbedded black chert and local chert-bearing limestone.
Present only in southwestern part of outcrop area where lower contact is gradational with silty limestone of Glenarie Formation. Thickness ranges from 0 to 9 m ft. Glenarie Formation Chadwick, - Medium-gray-weathering, medium- to dark-gray, fine-grained, thin- to medium-bedded, fossiliferous, silty limestone, and local chert lenses. Unit thickens to northeast.
Lower contact probably gradational. Thickness ranges from 17 to 52 m ft. Schoharie Formation Vanuxem, - Yellowish-gray- to locally pale-olive-weathering, medium- to dark-gray, medium- to thick-bedded, calcaeous siltstone and lesser amounts of silty limestone. Locally contains thin ribs or pods of black chert in limestone. Limestone content decreases in lower part of unit.
Contains the trace fossil Taonurus, a grazing trail. Lower contact gradational and placed at top of highest massive siltstone below lowest limestone. Thickness approximately 53 m ft. Skunnemunk Conglomerate Darton, - Grayish-purple to grayish-red, thin- to very thick bedded, locally cross-bedded, polymictic conglomerate and sandstone containing clasts of white vein quartz, red and green quartzite and sandstone, red and gray chert, and red shale; interbedded with medium-gray, thin-bedded sandstone and greenish-gray and grayish-red, mud-cracked shale.
Conglomerate and sandstone matrix is primarily hematite and microcrystalline quartz. Conglomerate cobbles range to Lower contact conformable and gradational as defined by Kummel and Weller About m 3, ft thick. Wantage Sequence Monteverde and Herman, - Restricted, discontinuous sequence of interbedded limestone, dolomite, conglomerate, siltstone, and shale.
New Mexico. Lower and Middle Santa Fe Group. Mostly Ordovician. Locally includes rocks of Early Devonian age at top. Lander County. Assignment of some rocks to the Havallah sequence in the East Range, Pershing County, is highly uncertain. Includes rocks ranging in age from Late Mississippian to Early Permian.
Southeast Humboldt County and northwest Lander County. Locally includes rocks of Silurian and Devonian age. In the East Range, Pershing County, consists of quartzite, conglomerate, slate, limestone, chert, and greenstone of the Inskip Formation Mississippian? Includes units such as Valmy Formation of north-central Nevada and some rocks mapped as Palmetto Formation in northern part of Esmeralda County and adjacent parts of Mineral and Nye Counties.
New York. Washington county: Whitehall Formation-dolostone, limestone; Ticonderoga Dolostone-chert. Beekmantown Group in part - In St. Glenerie Formation - limestone, chert.
Mount Merino and Indian River Formations - shale, slate, cherts. Mount Merino and Indian River Formations - shale, argillite, chert. Wappinger Group - including Fishkill limestone and dolostone : Copake Formation? Peebles Dolomite, Lilley and Bisher Formations, Undivided Silurian Peebles Dolomite, Lilley Formation, Bisher Formation, Undivided - Peebles Dolomite, bluish gray weathers light gray; planar to irregular, thick to massive bedded; 0 to feet thick; vuggy to cavernous porosity; cliffs former.
Lilley Formation, dolomite with minor limestone, chert, and shale; bluish gray to gray weathers reddish gray to gray; planar to irregular, thin to thick bedded; 20 to 80 feet thick; fossiliferous. Bisher Formation, dolomite with minor shale; bluish gray to gray weathers yellowish-orange; argillaceous and silty in part; planar to lenticular, thin to thick bedded; 20 to 90 feet thick; Interval ranges from 80 to feet in thickness. Wenlockian age of the Lilley Formation is based on 10 species of conodont fauna.
The Lilley consists of two main lithologies: 1 gray to blue gray, fine-grained argillaceous, variably fossiliferous uneven- to thin-bedded dolomite with dolomitic shale partings and 2 light-gray, medium to coarse-grained fossiliferous dolomite.
Thickness averages 15 m in Adams and southeastern Highland Cos. Eustatic sea-level fall in early to middle Wenlockian is proposed as the cause for shoaling during deposition. Traverse Group - Dolomite and shale interbedded with limestone; upper part dolomite; gray to light brown; thin to medium bedded; abundant chert; lower part shale interbedded with limestone; olive gray; thin to medium bedded; very fossiliferous; as much as feet thick. Same as Viola Limestone in Arbuckle Mountains.
ENID- Mostly orange-brown, fine- to medium-grained quartzose sandstone and conglomerate, grading northward into shale and calcitic siltstone. Thickness, about feet m. Thickness ranges from feet in south to feet or more in north.
Sumner Group LAWTON- "Garber Sandstone," Pg, reddish-brown, fine-grained sandstone and mudstone conglomerate, to feet 49 to 64 m thick, containing a basal sandstone, the "Asphaltum Sandstone Bed," about 10 to 60 feet 3 to 18 m thick.
Joe Group," limestone and shale. Joe 'Group,'" limestone and marlstone. Joe Group. Chert content increases southeastward. ENID- Mostly red-brown shale to north, grading into fine-grained sandstone and mudstone conglomerate southward into Logan County.
Thickness ranges from about feet in south to feet in north. Consists of amphibolite, micaceous quartzite, quartz schist, and recrystallized manganiferous chert. Includes structurally complex amphibole schist and quartz-rich hornblende gneiss of unknown age exposed at and near Chetco Peak west of Cave Junction Smith and others, Metamorphosed pelitic sedimentary rocks and subordinate metamorphosed submarine pillow lavas and pyroclastic beds of basaltic composition.
Metamorphic age is Early Cretaceous about Ma , according to Coleman , and protolith may be Jurassic or older in age. Consists of a variety of schistose rocks characterized by different proportions of muscovite, quartz, graphite, chlorite, actinolite, and epidote, rare thin layers of metachert, and clinozoisite-actinolite-albite-garnet metagabbro.
Potassium-argon age on muscovite from unit is about Ma Lanphere and others, and on a whole rock sample is about Ma Suppe and Armstrong, , indicating a Late Jurassic metamorphic age. Protolith is probably Triassic and Paleozoic in age. Black, green, and gray argillite, mudstone, and shale; graywacke, sandy limestone, tuff, and some coarse volcaniclastic rocks; chert, sandstone comprised of chert clasts, and chert pebble conglomerate; thin-bedded and massive limestone.
Locally contains some interbedded lava flows, mostly spilite or keratophyre. In places metamorphosed. Invertebrate marine fauna indicates unit mostly of Late Triassic Karnian and Norian age. Probably partly age correlative with rocks of the Applegate Group Wells and Peck, of southwestern Oregon. Structurally complex mixture of basaltic rocks, serpentinite, chert, argillite, conglomerate, silty sandstone, and lenses of marble composing the melange of the Takilma area of Smith and others Intermingled, commonly highly sheared metasedimentary, metavolcanic, and igneous rocks.
Includes serpentinite, altered gabbro, chert, siliceous phyllite, greenstone, and limestone. Highly sheared graywacke, mudstone, siltstone, and shale with lenses and pods of sheared greenstone, limestone, chert, blueschist, and serpentine. Identified as melange by some investigators. Epiclastic and volcaniclastic rocks, chert, limestone, and lava flows of mid- or Early Permian? Includes part of Hunsaker Creek Formation of Vallier , in the eastern Blue Mountains province, composed mostly of keratophyre flows, keratophyric volcaniclastic rocks and minor spilite, mudstone, and limestone.
In Wheeler County, includes phyllite, chert, and fusulinid-bearing crystalline limestone of probable Early Permian Wolfcampian? Sandstone, conglomerate, graywacke, rhythmically banded chert lenses.
Blake, Jr. Jayko unpublished data, in Curry and southern Coos Counties. Well-bedded limestone, fossiliferous cherty limestone, calcareous and carbonaceous sandstone, chert grit, argillite, and some conglomerate. In places foliated and metamorphosed. Includes fault slivers of Devonian rocks Kleweno and Jeffords, , Coffee Creek Formation of Mississippian age, Spotted Ridge Formation of Pennsylvanian age Merriam and Berthiaume, ; Mamay and Read, , and Paleozoic sedimentary and metamorphosed sedimentary and volcanic rocks, including sericite schist, amphibolite, and hornblende-garnet schist of Brown and Thayer Poorly bedded argillite, chert, phyllite, phyllitic quartzite, calc-phyllite, impure limestone, and marble.
In places rocks are strongly foliated. In Klamath Mountains of southwest Oregon, includes shale, mudstone, volcaniclastic sandstone, graywacke, conglomerate, tuff, and minor radiolarian chert and marble of the Applegate Group. Sparse fossils Fusilina, corals, and crinoids indicate that the unit includes rocks of Leonardian, Ochoan, and Late Triassic age OR In Baker County includes "sedimentary and volcanic rocks" MzPza of Brooks and others OR and metamorphosed sedimentary and minor volcaniclastic rocks containing mineral assemblages indicative of quartz-albite-muscovite-chlorite subfacies and quartz-albite-epidote-biotite subfacies of the greenschist facies.
Black to gray shale, mudstone, and sandstone with local lenses of pebble conglomerate. Overlies Josephine ophiolite of Harper unit Ju. Basalt flows, flow breccia, agglomerate, pillow basalt and pillow breccia, and lesser shale, chert, siltstone, and mudstone of ophiolitic complexes.
Lava flows, flow breccia, and agglomerate dominantly of plagioclase, pyroxene, and hornblende porphyritic and aphyric andesite. Includes flow rocks that range in composition from basalt to rhyolite as well as some interlayered tuff and tuffaceous sedimentary rocks.
Commonly metamorphosed to greenschist facies; locally foliated, schistose or gneissic. Considered to be accreted island-arc terrane. Allentown Formation Cambrian Allentown Formation - Medium- to medium-dark-gray, thick-bedded dolomite and impure limestone; dark-gray chert stringers and nodules; laminated; oolitic and stromatolitic; some orange-brown-weathering calcareous siltstone at base.
Buttermilk Falls Limestone through Esopus Formation, undivided - In descending order: Buttermilk Falls Limestone--gray fossiliferous limestone and black chert; Palmerton Sandstone--massive white siliceous sandstone; Schoharie Formation--gray calcareous, argillaceous siltstone; Esopus Formation--gray silty shale and sandy siltstone.
Gatesburg Formation - Gray dolomite, limestone, and sandstone. Leithsville Formation - Medium- to dark-gray, crystalline dolomite, light-olive-gray in places, weathering to light gray and yellowish brown; massive bedded; oolitic; pink to gray, mottled chert and dark-gray chert; thin shale and dolomitic shale interbeds; scattered sand grains; upper part is very shaly.
Mines Member of Gatesburg Formation - Gray dolomite containing siliceous "oolites" and chert having cryptozoon stromatolites. Nittany Formation - Medium- to dark-gray, thick-bedded dolomite containing chert and siliceous oolites. Ontelaunee Formation - Medium-dark-gray, finely crystalline dolomite, massive to finely laminated; weathers grayish yellow; thick-bedded, dark-gray chert at base. Ontelaunee Formation - Light- to dark-gray, very finely to medium-crystalline dolomite containing interbeds of light-gray limestone; interbedded nodular, dark-gray chert at base.
Richland Formation - Gray dolomite, in part oolitic, interbedded with medium-gray limestone and dark-gray oolitic chert. Rickenbach Formation - Medium- to dark-gray, coarsely crystalline dolomite in lower part; medium- to medium-light-gray, finely crystalline dolomite in upper part; chert lenses, beds, and nodules. Rickenbach Formation - Gray, very finely to coarsely crystalline, laminated dolomite; dark-gray chert in irregular beds, stringers, and nodules; bands of quartz sand grains in lower half.
Ridgeley Formation through Coeymans Formation, undivided - In descending order: Ridgeley Formation--white siliceous sandstone; Shriver Chert--gray siltstone and shale and dark-gray chert; Port Ewen Shale--dark-gray calcareous siltstone and shale; Minisink Limestone--dark-gray clayey limestone; New Scotland Formation--dark-gray fossiliferous shale and clayey limestone; Coeymans Formation--gray, clayey to sandy limestone. Rockdale Run Formation - Mostly limestone; some dolomite interbeds; some chert near middle and top; stromatolitic limestone in middle; pinkish marbleoid limestone and chert at base.
Shadygrove Formation - Pure, light-colored limestone, stromatolitic in part; abundant pinkish limestone and cream-colored chert. Paul Group - Very finely crystalline, "birdseye" limestone at top and base, granular fossiliferous limestone, black chert, and dolomite in middle.
South Dakota. Iron-Formation Proterozoic Paleoproterozoic Banded, dark-green, reddish-brown, and white iron-formation, ferruginous chert, and minor mica schist. Includes three or more ages of oxide-, carbonate-, silicate-, and sulifide-facies iron-formation and interbedded tuffaceous rocks.
Thickness ft m. Includes: Pahasapa Limestone Mississippian -White, light-gray to tan, fine- to medium-crystalline limestone and dolomite containing brown to gray chert. Solution features including collapse breccia, sinkholes, and caves are prevalent. Englewood Formation Mississippian to Dovonian - Pink, lavender to light-gray, thin- to medium-bedded, finely crystalline, argillaceous, dolomitic limestone.
Dark-green amphibolite, actinolite schist, and greenstone. Interflow units consists of graphitic schist, chert, and carbonate- and silicate-facies iron-formation. Thickness of individual flows ft , m. Dark-gray biotite schist, biotite-muscovite schist, pyritic biotite schist, and local massive chert beds. Thickness approximately ft , m.
Medium-gray to dark-greenish-gray phyllite, slate, and biotite schist containing minor chert and amphibolite. Locally intruded by thin metagabbro sills. Thickness 1,, ft m. Light-tan quartzite, siliceous schist, and minor chert.
Thickness , ft , m. Variegated, yellow to red, gray to brown, pink to purple, and black, interbedded sandstone, siltstone, shale, limestone, dolomite, calcarenite, chert and brecciated beds.
Thickness , ft m. Copper Ridge Dolomite Ordovician Copper Ridge Dolomite - Coarse, dark-gray, knotty dolomite, asphaltic in places; with much gray, medium-grained, well- bedded dolomite; abundant chert; cryptozoans typical.
Thickness about 1, feet. Copper Ridge Dolomite - Coarse, dark-gray, knotty dolomite, asphaltic in places, with much gray, medium-grained, well- bedded dolomite; abundant chert; cryptozoans typical. Devonian Formations - Characterized by marked north-south facies variations. Includes Pegram Formation - Thick-bedded, gray limestone and gray sandstone. Thickness 0 to 15 feet; Camden Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone.
Thickness 0 to about feet; Harriman Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. Harriman and Camden are differentiated paleontologically. Thickness 0 to 50 feet; Flat Gap Limestone - Thick-bedded, coarse-grained limestone, gray with red and brown grains.
Thickness 0 to 55 feet; Ross Formation - Siliceous limestone; gray and variegated shale; and medium-grained glauconitic limestone.
Thickness 0 to 75 feet. Devonian Formations - Characterized by marked north-south facies variations and by very irregular distribution.
Individual formations are not uniform in thickness and have been truncated by pre-Chattanooga erosion; includes Pegram Formation - Thick-bedded, gray limestone and gray sandstone. Thickness 0 to 30 feet; Camden Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. Thickness 0 to 13 feet; Ross Formation - Siliceous limestone; gray and variegated shale; and medium-grained glauconitic limestone.
Fort Payne Formation - Bedded chert, calcareous and dolomitic, somewhat crinoidal; and minor shale. Thin green shale Maury at base. Thickness about feet. Average thickness about feet. Fort Payne Formation - Bedded chert and calcereous and dolomitic silicastone; minor coarse-grained limestone and shale. Chattanooga Shale - Black carbonaceous shale, fissile. Thickness 0 to 70 feet. Fort Payne Formation - Calcareous and dolomitic silicastone; contains bedded chert, cherty limestone, and shale; scattered crinoidal limestone lenses.
Thickness to feet. Thickness 20 to 30 feet in most areas. Mapped as MDc in Flynn Creek structure, where it is about feet thick. Also mapped as MDc on the East Sheet. Fort Payne Formation - Bedded chert; calcareous and dolomitic silicastone; minor limestone and shale; scattered lenses of crinoidal limestone. Average thickness about feet in Wells Creek area ; and Chattanooga Shale - Black carbonaceous shale, fissile. Thickness 0 to 70 feet; average about 20 feet.
Monteagle Limestone - Mainly fragmental and oolitic, light-gray limestone; blocky bryozoan chert weathers from base. Louis Limestone - Residuum of nodules and blocks of chert in sandy clay. Originally grayish-brown, medium-bedded limestone. Maximum preserved thickness about 50 feet. Warsaw Limestone - Residuum of porous chert blocks in sandy clay.
Originally gray, medium- to coarse-grained, thick- bedded limestone. Thickness about 60 feet. Wells Creek Formation - Gray limestone and dolomite, with angular chert blocks and fragments; and minor shale, mottled red and green, calcareous. Thickness 0 to 50 feet. Present only in Sequatchie Valley.
Maximum exposed thickness in Sequatchie Valley feet. Caballos Novaculite and Maravillas Chert, undivided. Carrizo Mountain Group showing metasedimentary rocks. Edwards and Comanche Peak Limestones, undivided. Mississippi, Devonian, and Ordovician rocks, undivided. Washita and Fredericksburg Groups, undivided. Mississippian 1 carbonate rocks in southwestern Utah Mississippian. Chepultepec and Copper Ridge Formations - Dolomite, minor limestone, chert, and calcareous sandstone.
Edinburg Formation, Lincolnshire and New Market Limestones - Black limestone and shale; gray limestone, in part cherty.
Greenbrier Limestone - Limestone, in part cherty, fossiliferous; shale. Knobs Formation, Paperville Shale, Lenoir and Mosheim Limestone - Sandstone, conglomerate, siltstone; black, fissile shale; and limestone, in part cherty. Knox Group - dolostone, limestone, sandstone. Mascot and Kingsport Dolomites - Dolomite, chert, and minor limestone.
Moccasin or Bays Formation through Blackford Formation - Dusky-red shale and mudstone; sandstone; limestone, in part cherty; and calcareous shale. Nolichucky and Honaker Formations - Dolomitic shale; dolomite and minor chert.
Tomstown Dolomite - Dolomite, in part cherty. Waynesboro Formation and Tomstown Dolomite - Waynesboro Formation: Dolomite, dusky-red and green shale, limestone, and sandstone. Tomstown Dolomite: Dolomite, in part cherty. Clarendon Springs, Ticonderoga, and Rock River Dolomites; Gorge Formation Cambrian Clarendon Springs, Ticonderoga, and Rock River Dolomite; Gorge Formation - Fairly uniform, massive, smooth weathered gray dolomite characterized by numerous geodes and knots of white quartz; quartz sandstone and irregular masses of chert are near the top.
The Gorge is a partly conglomeratic facies on the west limb of the St. Albans synclinorium.. Hathaway Formation - Gray to black argillite and bedded radiolarian chert, with included blocks and fragments of chert, limestone, dolomite, sandstone and graywacke.
Carboniferous and Permian volcanic rocks Devonian to Permian; Triassic in Asotin County Predominantly altered andesite, basalt, and diabase with interbedded chert and argillite; includes some tuff, greenstone, and spilitic volcanic rocks; northern Cascade Mountains.
Mostly schistose greenstone, some agglomerate, and rarely lapilli; includes minor beds of limestone with associated argillite and graywacke; northwestern Stevens County. Heat treating can be applied for workability, but does not seem to be a feature of prehistoric use in general.
I have chosen to give a separate category to Ohio area flints for several reasons. One, I am personally quite familiar with these materials and, two, they comprise some of the best and most used and traveled of all prehistoric source materials in the eastern U.
As a result, it is subject to heat treating as almost a requirement to make it workable, due to its very tough consistency. This subject is also addressed in the instructional video for Traditional Flintknapping which can be previewed and purchased directly through this website. As a fairly deep pit is required to obtain this material, it does not appear to have been chosen for use much prior to Archaic times, although there are apparently some Paleo-Indian pieces here.
Its basic color is white to off-white when quarried. However, flint ridge material is most readily identified by the brilliant colors virtually the entire pastel palette when fired. Bright reds, greens, oranges, and many other darker colors blend into the whites once fired, making it perhaps the most striking of all such quarried flints.
Firing also results in an extremely glossy texture , another distinctive characteristic. Flint Ridge material is of good to excellent workability, once fired.
Otherwise it is very tough and difficult to flake generally. Individual quarry sources can often be readily identified by color and texture. Obviously part of the original deposits that include flint ridge in central Ohio, these sources are found mostly in eastern and east-south Ohio. In general, Upper Mercer Mercer County being the type name flints are characterized by narrower color ranges from medium gray with shades of blue to medium to dark bluish gray with cream colored streaking.
When fired, it is extremely glossy in texture, easily workable and was a favorite of Paleo-Indian and later peoples throughout the upper Ohio Valley and beyond. This source is almost always a very glossy jet black when fired. However, it is characterized by distinctive orange flecking, rather than streaking, produced by the oxidizing out of small iron pyrites found in this particular source.
Its distribution is less widespread, but the quality and workability is good to excellent, and it was also a favorite choice in all early periods. Ohio River Valley assemblages from early Archaic periods and later frequently contain a high percentage of artifacts from this broad collection of nondescript cherts. Early Archaic flintknappers seem to have had better knowledge of the best sources of this stone than later peoples. In general this stone is characterized by a medium buff to tan color with light green streaking, although grays and yellowish types are not uncommon.
The pale green banding is, however, distinctive, and it appears this source material was easily obtained along the Ohio River counties and was also workable without heat treating, perhaps accounting for its desirability, despite its overall lack of quality.
In terms of workability it is only poor to good, depending on the source location of the more easily accessed outcrops. These people chose to make very small projectile points for their arrows when widespread warfare made accessibility to more distant sources risky. Pebble cherts were obtained directly from deposits along the main river, washed down from many sources as far away as Pennsylvania.
In general, brownish cobble cortex can be seen remaining, as the workability of these cherts is often very poor, despite their overall appearance of quality.
However, many small artifacts of glossy and exotic materials can be found throughout the Ohio Valley area made from these pebble cherts. Not even a chert, these are large depositional materials of layered non-limestone related materials. They are exclusively black, and often large tools will reveal significant whitish cortex. Additionally, extremely large blocks, often weighing several tons, can be found in the tributaries of the upper Kanawha River above Charleston, WV such as Campbell's Creek and Paint Creek.
However, this material is generally of poor quality for chipping. Only the extremely weathered material that had been exposed for thousands of years was selected by Native American flintknappers. Sometimes the best of this material is quite glossy when flaked, but other samples indicate attempts to improve the workability by firing, with some redness revealed.
However, firing does not seem to bring the glossiness or color range, due to the absence of pyrites and other inclusions. While useful to prehistoric peoples because of its widespread distribution and easy availability, it is of generally poor quality and difficult to work. The texture is reminiscent of slate or basalt, however, and it does produce a quality sharp edge when flaked.
I have, however, seen excellent Early Archaic and even Paleo-Indian pieces of this material, indicating a high degree of competence on the part of those early flintknappers, as well as an intimate knowledge of the few good sources of this widespread material.. This is a gray material similar in color and texture to the Onandaga described above, and is often misidentified as such. However, it is generally more of a cobble deposited chert with a quite grainy and difficult to flake nature, unless obtained directly from the few eastern WV deposits.
In eastern KY. This distinctive flint is found in the karst limestone pits of that county and is characterized by a honey-amber color that is unique to the region. It is also recognized and distinguished from some nearby brush creek varieties by the higher quality of its texture and by a quite distinct maroon flecking found only in this source material. Its workability is only fair to good. This type, though not as glossy when fired, is easily characterized by its recognizable brilliant forest-green banding with oranges and other colors brought out when fired.
Its workability can be good to very good, and the distribution of this type throughout the western part of the state is fairly consistent, although few pieces made their way far upriver.
While the color is distinctive, as indicated in the name, the actual depositional relationship to the more clearly defined Indiana variety described below is not always clear, since their ranges frequently overlap.
This material is found in large, round nodules in several locations within that county. It runs the color range from dull white poorer quality to the full range of grays from light to dark. It is glossy without firing and is some of the most workable raw material to be found. Other varieties of red and green, often referred to as hornstone are also identified in counties farther removed from the Ohio Valley counties in the interior of central and western Indiana.
It was also a favorite of native peoples from Paleo times to late prehistoric, and its distribution several hundred miles from the quarry site is indicative of its desirability. This quality enabled unusually large artifacts to be chipped, and some of the best known flint caches in all of American archeology are of this distinctive gray material.
Those excavated cherts when fired frequently supply some of the best and most colorful flints to be found in all of North America.
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