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Erwin and Hampton Formations
Erwin Formation (Keith, 1903,1907). Quartzite, sandstone, and shale. Quartzite, light-gray to white, medium- to fine-grained, thick-bedded, cross-laminated, quartz cemented, and very resistant. Sandstone, ferruginous, dark-gray to bluish- black, medium- to coarse-grained, locally conglomeratic, and with various amounts of hematite cement, in medium- to thick-beds. Shale, silty and sandy, drab-greenish-gray, thin- to medium-bedded, non-resistant, comprises much of the formation but is poorly exposed. The Erwin is less than 1000 feet thick and is equivalent to the Antietam Formation and possibly the upper part of the Harpers Formation in northern Virginia. Hampton Formation (Keith, 1903). Shale, sandstone, and quartzite. Shale, dark-gray or dark-greenish-gray, fissile, very argillaceous, silty laminae common, with interbeds of siltstone and fine-grained, lithic sandstone. Sandstone, feldspathic, greenish-gray, vitreous, medium- to coarse-grained, pebbly, cross-laminated. Quartzite, white to light-brown, vitreous, fine-grained, medium- to thin-bedded, resistant, restricted to the upper part of the formation. The Hampton is largely equivalent to the Harpers Formation to the northeast and ranges in thickness from more than 1500 feet to about 1200 feet with the thinner sequence in the northwesternmost exposures.
||Erwin and Hampton Formations
Sedimentary > Clastic > Sandstone
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Sedimentary > Clastic > Mudstone > Shale
||Appalachian Plateaus and Valley and Ridge
Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000.
Virginia Division of Mineral Resources, 2003, Digital Representation of the 1993 Geologic Map of Virginia, Publication 174, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, scale 1:500,000.
Carroll - Floyd - Grayson - Montgomery - Pulaski - Smyth - Washington - Wythe