Geologic units in Pushmataha county, Oklahoma

Jackfork Group or Jackfork Sandstone (Early Pennsylvanian) at surface, covers 37 % of this area

ARDMORE-SHERMAN- "Jackfork Sandstone"- Sandstone, gray, white, and tan, coarse-grained, cherty, with gray shale and some boulders up to 7 feet in diameter; thickness 1,150 to 5,000 feet Occurs in the OUACHITA MNTS. McALESTER TEXARKANA- "Jackfork Group"- Sandstone, tan to gray, fine- to coarse-grained, quartzose, with some mica, poorly to well-indurated, quartzitic has some gray shale and several maroon shales; black, white-speckled "Chickasaw Creek Chert" is at base; thickness, 1,500 to 6,000 feet or more. Occurs in the OUACHITA MTNS SOUTH OF TI VALLEY FAULT.

Stanley Group or Stanley Shale (Mississippian) at surface, covers 19 % of this area

ARDMORE-SHERMAN- "Stanley Shale"- Shale, dark-gray, siliceous,with some gray to buff fine-grained sandstones; thickness,10,000 feet Occurs in the OUACHITA MNTS. McALESTER TEXARKANA- "Stanley Group"- Shale, olive-green to gray, illitic, chloritic, with many5- to 30-foot-thick beds of poorly sorted, micaceous, quartzose sandstones and some thin siliceous cherty beds and black shales; several tuff beds occur in basal 1,000 feet and are indicated by red line in Stanley exposures as designated on map; many asphaltite, lead, and quartz veins occur along fault zones; mostly Chesterian age; thickness, 7,500 to 14,000 feet or more. Occurs in the OUACHITA MTNS SOUTH OF TI VALLEY FAULT.

Lynn Mountain Formation (Early Pennsylvanian) at surface, covers 12 % of this area

McALESTER TEXARKANA- Shale, gray to tan, with many fine- to coarse-grained, quartzose, micaceous sandstone with many bottom markings; top eroded; thickness, 3,000 to 7,000 feet or more; unconformable upon Goddard, Delaware Creek, Woodford, and older beds that are exposed north and west of Ti Valley Fault. Occurs in the OUACHITA MTNS.

Terrace Deposits (Pleistocene) at surface, covers 11 % of this area

WOODWARD- Lenticular and interfingering deposits of light-tan to gray gravel, sand, silt, clay, and volcanic ash. Sand dunes are common in many places. Thickness ranges up to 150 feet and averages about 60 feet. ENID- Sand, silt, clay, and gravel. Maximum thickness, about 75 feet (23 m) along major streams. TULSA- Fine gravel, sand, silt, and clay. CLINTON- Stream-laid deposits of sand, silt, clay, gravel, and volcanic ash; thickness ranges from 0 to about 120 feet. OKLAHOMA CITY- Lenticular beds of sand, silt, clay, and gravel. Thickness ranges from a few feet to about 100 feet and probably averages about 50 feet along major streams. FORT SMITH- Gravel, sand, silt, and clay. LAWTON- Sand, clay, and gravel as much as 75 feet (23 m) in Tillman County, ranging from 5 to 50 feet (2 to 15 m) elsewhere. ARDMORE-SHERMAN- Gravel, sand, silt, clay, and volcanic ash; thickness, about 5 to 50 feet; at various levels, as high as 160 feet above present flood plains. McALESTER TEXARKANA- Gravel, sand, silt, clay, and volcanic ash; several levels 20 to 160 feet or more above present flood plains, with each level containing deposits that average 20 to 30 feet in thickness, some windblown sand on top; may include colluvial wash down sides of hills.

Antlers Sand or Antlers Sandstone (Early Cretaceous) at surface, covers 9 % of this area

ARDMORE-SHERMAN- "Antlers Sand" Sand, white to yellow, medium-grained, weakly indurated, with varicolored clays. Contains arkosic conglomerates near Arbuckle Mountains and "Baum Limestone" near Mannsville anticline. Thickness, 200 to 700 feet. McALESTER TEXARKANA- "Antlers Sandstone" Sandstone and sand, white to reddish-yellow to orange-brown to gray, fine- to coarse-grained, quartzose, crossbedded, moderately to weakly indurated, interbedded with varicolored clays and conglomerates; contains fossil wood and dinosaurs; rests unconformably upon Ouachita rocks but conformably upon DeQueen Limestone; thickness, 0 to 320 feet, thickening southeastward to 900 feet in subsurface.

Alluvium (Holocene) at surface, covers 8 % of this area

WOODWARD- Lenticular and interfingering deposits of gravel, sand, silt, and clay. Generally light-tan to gray. Thickness along major streams ranges up to 100 feet and probably averages 40 feet; along minor streams the thickness ranges up to 45 feet and probably averages 20 feet. ENID- Sand, silt, clay, and locally gravel. Maximum thickness ranges from 30 to 80 feet (9 to 24 m) along major streams and from 0 to 60 feet (0 to 18 m) along minor streams. TULSA- Gravel, sand, silt, and clay. TULSA- Gravel, sand, silt, and clay. OKLAHOMA CITY- Sand, silt, clay, and lenticular beds of gravel. Thickness ranges from about 30 to 100 feet and probably averages about 50 feet along major streams. Along minor streams, thickness ranges from a few feet to about 50 feet and probably averages about 25 feet. LAWTON- Sand, clay, and gravel as much as 50 feet (15 m) thick; Shown only along major streams and tributaries. ARDMORE-SHERMAN- Gravel, sand, silt, and clay, including low terraces; thickness, about 25 to 100 feet. McALESTER TEXARKANA- Gravel, sand, silt, and clay, including low terraces about 30 feet above channels; thickness, about 50 feet along Little River and 110 feet along Red River.

Johns Valley Formation or Johns Valley Shale (Early Pennsylvanian) at surface, covers 2 % of this area

ARDMORE-SHERMAN- "Johns Valley Formation"- Shale, dark-gray, with boulder conglomerate; thickness, 425 to 900 feet. Occurs in the OUACHITA MNTS McALESTER TEXARKANA- "Johns Valley Shale"- Shale, dark-gray, with some stringers of Wapanucka-like limestone in northwestern part of area; contains exotic boulders of southern Arbuckle Mountain facies, ranging from Fort Sill to Goddard and as large as 369 feet in diameter; some Wapanucka nodules are not exotic but were formed in place; thickness, 300 to 1,000 feet. Occurs in the OUACHITA MTNS SOUTH OF TI VALLEY FAULT.

Arkansas Novaculite (Early Mississippian to Early Silurian) at surface, covers 0.6 % of this area

McALESTER TEXARKANA- Chert, fine- to very fine-grained, gray, green, tan, black, white, and pink, with interbedded black to gray shale in 1-to 18-inch beds; some interbedded conglomerates and in places a basal conglomerate; upper part has been determined to be Mississippian in age and lower part to be Early Silurian, on basis of examination of palynomorphs from Potato Hills; thickness, 600 feet or more. Occurs in the OUACHITA MTNS SOUTH OF TI VALLEY FAULT.

Bigfork Chert (Middle Ordovician) at surface, covers 0.4 % of this area

ARDMORE-SHERMAN- Limestone, gray, and dark-gray to black chert; thickness, 575 feet. Occurs in the OUACHITA MNTS. McALESTER TEXARKANA- Chert, dark-gray to black, with interbedded graptolitic black shales and fossiliferous gray to black cherty limestones; contains asphaltite seams; erodes into a mappable escarpment; thickness, 600 to 800 feet. (Same as Viola Limestone in Arbuckle Mountains.) Occurs in POTATO HILLS, BROKEN BOW UPLIFT or ADJACENT SMALLER UPLIFTS IN SOUTHEASTERN PART OF OUACHITA MOUNTAINS.

Missouri Mountain and Polk Creek Shales (Early Silurian to Late Ordovician) at surface, covers 0.4 % of this area

McALESTER TEXARKANA- Shale, greenish-gray to maroon to black; grades into phyllite in Broken Bow Uplift; contains some thin sandstones and gray conglomerates; a fossiliferous limestone occurs in Southeast quarter section 29, Township 4 South, Range 23 East; mapped as SmOp in Potato Hills, where it is included with Polk Creek Shale; thickness, 60 to 110 feet or less. Occurs in POTATO HILLS, BROKEN BOW UPLIFT or ADJACENT SMALLER UPLIFTS IN SOUTHEASTERN PART OF OUACHITA MOUNTAINS.

Womble Formation or Womble Shale (Middle Ordovician to Early Ordovician) at surface, covers < 0.1 % of this area

ARDMORE-SHERMAN- "Womble Shale"- Shale, black to green; thickness, 250 feet, base covered. Occurs in the OUACHITA MNTS. McALESTER TEXARKANA- "Womble Formation"- Sandstone, phyllites, and shales, greenish-gray to dark-gray to black, weathering red-brown; some black to brown cherty limestones occur in upper part; Middle Ordovician graptolites are found in upper part, and Lower Ordovician graptolites in lower part; basal part faulted; estimated thickness, 1,000 feet or more, with maximum thickness in Arkansas 3,500 feet. Occurs in POTATO HILLS, BROKEN BOW UPLIFT or ADJACENT SMALLER UPLIFTS IN SOUTHEASTERN PART OF OUACHITA MOUNTAINS.

Goodland Limestone and Walnut Clay (Early Cretaceous) at surface, covers < 0.1 % of this area

ARDMORE-SHERMAN- "Goodland Limestone," limestone, gray, dense, nodular to massive; thickness, 20 to 30 feet. At base is "Walnut Clay," tan clay, about 4 feet thick. McALESTER TEXARKANA- Limestone, white, fine crystalline, massive-bedded, with "Texigryphaea mucronata;" some argillaceous buff beds in lower few feet may be "Walnut Clay" equivalents; erodes into a mappable escarpment; thickness, 26 to 55 feet.