Breathitt Formation is informally elevated to group rank and subdivided into the following eight informal formations: Pocahontas, Bottom Creek, Alvy Creek, Grundy, Pikeville, Hyden, Four Corners, and Princess formations. Hyden includes the Kendrick Shale Member (reassigned) at its base, the lower Whitesburg coal, member I, upper Whitesburg coal, member J, Fire Clay coal, member K, Fire Clay rider coal, member L, Hamlin coal, shale member M, and Taylor coal. Age is Middle Pennsylvanian (Atokan). [Revisions made in this paper are strongly contested by C. Rice and other USGS scientists who work in this area (oral commun., 9/3/93).]

Source: GNU records (USGS DDS-6; Reston GNULEX).

Hyden Formation of Breathitt Group is formally named in this report for town in Leslie Co., southeastern KY. Consists of coal-bearing rocks that overlie Pikeville Formation (new) and underlie Four Corners Formation (new). Extends into TN, VA, and WV and includes Kendrick Shale Member at its base throughout. Coals range from the Whitesburg through Copland. Reaches a maximum thickness of <260 m. Thins to the north and is difficult to differentiate from adjacent units in northeastern KY. According to the author, formal nomenclature presented in this report for units occurring in KY has been accepted by the Kentucky Stratigraphic Nomenclature Committee. Units that occur largely outside KY are considered informal. Report includes correlation charts, cross sections, and measured sections.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Fluvio-deltaic Pikeville, Hyden, and Four Corners Formations of the Breathitt Group in eastern KY represent three superimposed 3rd-order composite sequences, their unconformable boundaries corresponding with maximum flooding. The Breathitt is up to 950 m thick in eastern KY and comprises delta-plain facies of siltstone, clay-rich shale, sandstone, coal, siderite, and rare limestone. Calculated average ages of the base and the top are 323 Ma and 303 Ma. The four major marine members at the bases of the Pikeville, Hyden, Four Corners, and Princess Formations (Betsie, Kendrick, Magoffin, and Stoney Fork) are estimated to occur at 2.5 Ma intervals, which equates with the 3rd-order cyclicity of Vail and others (1977).

Source: GNU records (USGS DDS-6; Reston GNULEX).

Hyden Formation of Breathitt Group of Chesnut (1992); Hyden unit (informal) in Breathitt Formation of Rice and others (1994, GSA Spec. Paper, p. 130, citing Chesnut, 1989). Not used. [Rocks assigned to the Hyden Formation by Chesnut (1992) are in middle of Breathitt Formation, from base of Magoffin Member (= top of Taylor, Copland, Limestone, or Sharp coals) down to base of Kendrick Shale Member.]

Source: Publication.

Corr. chart. Hyden Formation of Breathitt Group. Mostly sandstone, siltstone, shale, and coal. Recognized in eastern and southeastern Kentucky. Lies below Four Corners Formation and above Pikeville Formation, both of Breathitt Group. Age is Middle Pennsylvanian (Westphalian; Atokan).
In eastern Kentucky includes (descending) Copland (Taylor) coal bed, Hamlin coal zone, Fire Clay rider coal, Fire Clay (Hazard No. 4) coal bed, Whitesburg coal bed, and Kendrick Shale Member at base.
In southeastern Kentucky [Upper Cumberland River district] includes (descending) Sharp (Limestone) coal bed, Jesse Sandstone Member, Copper Spur (Pardee) coal bed, Smith coal zone, Wallins Creek (Phillips) coal zone, Stray coal zone, Puckett Sandstone Member, and Kendrick Shale Member at base.
[Peppers (1996, GSA Memoir 188, p. 9, pl.) placed beds approx = Hyden (btw. the Haddix and Amburgy coals; below the Winifrede coal of West Virginia) in upper part of Westphalian B and lower part of Westphalian C, MICRORETICULATISPORITES NOBILIS-FLORINITES JUNIOR (NJ) to TORISPORA SECURIS-T. LAEVIGATA (SL) miospore assemblage zone of western Europe. Eble and others (2009, Kentucky Geol. Survey, ser. XII, Spec. Pub. 10, fig. 5.2) placed the Winifrede coal zone of West Virginia at the Duckmantian/Bolsovian (Westphalian B/C) boundary on basis of miospores.]
[See also Chesnut, 1997 (revised Oct. 12, 1999), Stratigraphy of the coal-bearing strata of the Eastern Kentucky coal field, available online through the Kentucky Geol. Survey (http://www.uky.edu/KGS/coal/coalcorrel.htm) and geologic descriptions of stratigraphic units in the Kentucky Geological Survey database (http://kgs.uky.edu/kgsmap/KGSLitho/lithoSearch.asp#).]

Source: Publication.