Maccrady Shale (VAMm;0)

State	Virginia
Name	Maccrady Shale
Geologic age	Mississippian
Original map label	Mm
Comments	Appalachian Plateaus and Valley and Ridge. From expanded explanation (ref. VA002): Maccrady Shale (Stose, 1913). Shale, siltstone, minor limestone, and sandstone. Shale and siltstone, light-grayish red, few light-greenish-gray beds, silty, very-thin- to medium bedded, indistinctly bedded, interbedded. Collapse breccia in middle of formation, with anhydrite (?) locally in western Tazewell County (Windolph, 1987). Limestone, dolomitic, light-yel lowish-brown and bluish-gray in Washington and Tazewell counties. Sandstone, light- to medium-gray, fine to coarse-grained, locally cross-bedded. Maccrady sparsely fossiliferous including a fish-bone bed (Bartlett, 1974, p. 101). Contains salt, anhydrite, and economic deposits of gypsum where the formation is thickest and folded and faulted in Smyth County (Sharpe, 1984; Stose, 1913). Basal beds locally interfinger with and are gradational with underlying Price Formation and lie on progressively older units of the Price west of a line from north astern Tazewell County through central Washington County (Bartlett, 1974, p. 99). Maccrady thins northwestward, but locally thins southwestward (Warne, 1990). It wedges out at the southwest corner of Virginia (Englund, 1979); in northern and western Washington and northwestern Smyth counties the Maccrady is less than 50 feet thick (Averitt, 1941; Warne, 1990), but it is as much as 2000 feet thick to the northeast in Smyth County (Sharpe, 1984), and at least 1000 feet thick in a partial section in Montgomery County (Bartholomew and Lowry, 1979).
Primary rock type	shale
Secondary rock type	siltstone
Other rock types	evaporite; limestone; mudstone; sandstone
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shale Minor Sedimentary > Clastic > Siltstone Incidental Sedimentary > Carbonate > Limestone Sedimentary > Chemical > Evaporite Sedimentary > Clastic > Mudstone Sedimentary > Clastic > Sandstone
Map references	Digital Representation of the 1993 Geologic Map of Virginia", 2003, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, viewing software not included. This is a digital version of "Geologic Map of Virginia" published in 1993. Available from: https://www.dmme.virginia.gov/commerce/ [https://www.dmme.virginia.gov/commerce/]
Unit references	Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000 Digital Representation of the 1993 Geologic Map of Virginia - expanded explanation: 2003, Commonwealth of Virginia, Department of Mines, Minerals, and Energy, Divsion of Mineral Resources, Publication 147, 85 pp Digital Representation of the 1993 Geologic Map of Virginia", 2003, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, viewing software not included. This is a digital version of "Geologic Map of Virginia" published in 1993. Available from: https://www.dmme.virginia.gov/commerce/ [https://www.dmme.virginia.gov/commerce/]
Geographic coverage	Alleghany - Montgomery - Pulaski - Wythe