GEOLEX

Summary of Citation: Gunsight

Publication:
Plummer, F.B., 1919, Preliminary paper on the stratigraphy of
   the Pennsylvanian formations of north-central Texas, with
   discussion: American Association of Petroleum Geologists
   Bulletin, v. 3, p. 132-150

Usage in Publication:
Gunsight limestone member

Modifications:	Geologic Province:	Dominant Lithology:
First used	Bend arch	Limestone

Summary:
First used; intent to name not stated, and no type locality designated. Probably named for Gunsight, Stephens Co, TX on Bend arch. First used as upper member of Gunsight formation (first used), which is third from base of 7 formations of Upper Pennsylvanian Cisco division in Brazos River Valley area. These formations compare with Drake's (1893) Colorado Valley section as follows:

Summary of Citation: Gunsight

Publication:
Plummer, F.B. and Moore, R.C., 1922, Stratigraphy of the
   Pennsylvanian formations of north-central Texas: University
   of Texas Bulletin, no. 2132, 237 p.

Usage in Publication:
Gunsight limestone [member]

Modifications:	Geologic Province:	Dominant Lithology:
Named	Bend arch	Limestone Shale

Summary:
Named Gunsight limestone [member] of newly named Graham formation of Cisco group (revised). In Colorado River Valley Graham formation is divided into following members (ascending): Bluff Creek shale, Gunsight limestone, and Wayland shale. In Brazos River Valley Graham is divided into following members (ascending): Finis shale and sandstone, Jacksboro limestone, Gonzales Creek shale and sandstone, Bunger limestone, South Bend shale and sandstone, Gunsight limestone, and Wayland shale. Type locality designated at Gunsight, Stephens Co, TX, where upper limestone layer is a uniformly thin, light-yellowish-gray, densely crystalline bed weathering to smooth-surfaced blocks. Lower layer is separated from upper by 22 ft of soft yellow clay shale and consists of soft-white or light-buff limestone, in most places filled with CAMPOPHYLLUM TORQUIUM [coral] which weather out abundantly. [This is the CAMPOPHYLLUM Bed of Drake (1893).] Gunsight varies somewhat in different counties but commonly consists of two thin limestone layers separated by 20-25 ft of yellow shale. Traced from Jack Co (Ft. Worth syncline) to Young, Stephens, and Eastland Cos (Bend arch). Traced south of the Cretaceous overlap across Brown Co, in Coleman Co, and to Bend outcrop in McCulloch Co (Llano uplift). Stratigraphic chart. Measured sections. Pennsylvanian age.

Summary of Citation: Gunsight

Publication:
Barnes, V.E., 1967, Geologic atlas of Texas, Sherman Sheet;
   Walter Scott Adkins memorial edition: University of Texas-Austin,
   Bureau of Economic Geology, 1 sheet, scale 1:250,000

Usage in Publication:
Gunsight Limestone

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits Mapped 1:250k	Fort Worth syncline	Limestone

Summary:
Is Pennsylvanian unit [unranked] mapped separately near top of Graham and Caddo Creek Formations (mapped undivided) in southwestern part of map sheet in northeastern Jack Co, TX (Fort Worth syncline). [May be mapped in northwesternmost Wise Co, TX and southwestern Montague Co, TX, however, map unit is not clearly labeled.] Is described as limestone--aphanitic, hard, thick-bedded, pale to moderate yellowish brown; sparsely crinoidal; thickness 1-4 ft, cut out locally by channels filled with sandstone, map unit P(?)ss.

Summary of Citation: Gunsight

Publication:
Barnes, V.E. (project director), 1987, Geologic atlas of Texas,
   Wichita Falls-Lawton Sheet; Alfred Sherwood Romer memorial
   edition: University of Texas-Austin, Bureau of Economic
   Geology, 1 sheet, scale 1:250,000

Usage in Publication:
Gunsight Limestone

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits Mapped 1:250k	Bend arch Fort Worth syncline	Limestone

Summary:
Mapped as a single line [as an unranked unit] in Thrifty and Graham Formations (mapped undivided) of Cisco Group in the southeastern part of the mapped area. Called "Lower Gunsight Limestone." Present in four widely separated exposures--correlation between exposures is imprecise, being based solely on stratigraphic position: a) in southern Young Co, TX on Bend arch, 1-3 ft thick; b) northwest of Jacksboro, Jack Co, TX on Fort Worth syncline, 1-3 ft thick; c) immediately east of State Route 148, Jack Co, 1-5 ft thick; and d) immediately east and west of State Route 59, eastern Jack Co, 2-5 ft thick. Of Virgil age (Late Pennsylvanian). Geologic map.