Marcellus Shale and Needmore Formation (VADmrn;0)

State	Virginia
Name	Marcellus Shale and Needmore Formation
Geologic age	Devonian
Original map label	Dmrn
Comments	Appalachian Plateaus and Valley and Ridge. From expanded explanation (ref. VA002): Marcellus Shale and Needmore Formation. Marcellus Shale (Hall, 1839; Butts and Edmundson, 1966). Shale, dark-gray to black, more or less fissile, pyritic. Thickness estimated to be 500 feet in Frederick County and 350 to 400 feet in the Massanutten synclinorium (Rader and Biggs, 1976). Needmore Formation (Willard, 1939). Shale, dark or greenish gray, with thin beds or nodules of black, argillaceous limestone and the Tioga metabentonite beds (Dennison and Textoris, 1970), generally present with the Millboro or Marcellus Shale and is disconformable with the underlying Ridgeley Sand tone. Thickness ranges from 0 to 160 feet and is replaced to the southwest by the Huntersville Chert.
Primary rock type	black shale
Secondary rock type	shale
Other rock types	bentonite; limestone
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shale > Black-shale Sedimentary > Clastic > Mudstone > Shale Incidental Sedimentary > Carbonate > Limestone Sedimentary > Clastic > Mudstone > Claystone > Bentonite
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", 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	Frederick - Page - Rockingham - Shenandoah