Ramseyburg Member

(Drake and Epstein, 1967) - Interbedded medium- to dark-gray, to brownish-gray, fine- to medium-grained, thin- to thick-bedded graywacke sandstone and siltstone and medium- to dark-gray, laminated to thin-bedded shale and slate. Unit may form complete turbidite sequences, Tabcde (Bouma, 1962), but basal cutout sequences Tcde dominate. Basal scour, sole marks, and soft-sediment distortion of beds are common in graywacke. Thermally metamorphosed near intrusive bodies. Lower contact placed at bottom of lowest thick- to very thick bedded graywacke, but contact locally grades through sequence of dominantly thin-bedded shale and slate and minor thin- to medium-bedded discontinuous and lenticular graywacke beds in the Bushkill member. Parris and Cruikshank (1992) correlate unit with Orthograptus ruedemanni to lowest part of Climacograptus spiniferus zones of Riva (1969, 1974). Thickness ranges from 640 m (2,100 ft) in Delaware River Valley, to 1,524 m (5,000 ft) near Stillwater, to 1067 m (3,500 ft) at New York State line.
State New Jersey
Name Ramseyburg Member
Geologic age Upper and Middle Ordovician
Lithologic constituents
Sedimentary > Clastic > Sandstone > Graywacke (Bed)
Sedimentary > Clastic > Siltstone (Bed)
Metamorphic > Metasedimentary > Metaclastic > Slate
Sedimentary > Clastic > Mudstone > Shale (Bed)
Comments Martinsburg Formation

Dalton, R.F., Herman, G.C., Monteverde, D.H., Pristas, R.S., Sugarman, P.J., and Volkert, R.A., 1999, New Jersey Department of Environmental Protection, Bedrock Geology and Topographic Base Maps of New Jersey: New Jersey Geological Survey CD Series CD 00-1; ARC/INFO (v. 7.1), scale 1:100,000.

Drake, Avery A. Jr.,Volkert, Richard, A., Monteverde, Donald H., Herman, Gregory C., Houghton,Hugh F., Parker, Ronald A., and Dalton, Richard F., 1996, Bedrock Geologic Map of Northern New Jersey: U.S. Geological Survey Miscellanenous Investigations Map I-2540-A, 4 cross sections, 2 sheets, size 56x40; 58x41, scale 1:100.000.


Drake, A.A., Jr., and Epstein, J.B., 1967, The Martinsburg Formation (Middle and Upper Ordovician) in the Delaware Valley, Pennsylvania-New Jersey: U.S. Geological Survey Bulletin 1244-H, p.H1-H16.


Bouma, A.H., 1962, Sedimentology of some flysch deposits; a graphic approach to facies interpretation: New York, Elsevier Publishing Co., 168 p.

Riva, John, 1969, Middle and Upper Ordovician graptolite faunas of St. Lawrence lowlands of Quebec and Anticosti Island, in Kay, Marshall, ed., North Atlantic; geology and continental drift: American Association of Petroleum Geologists Memoir 12, p. 513-556

Riva, John, 1974, A revision of some Ordovician graptolites of eastern North America: Paleontology, v.17, pt. 1, p.1-40.

Parris, D.C., and Cruikshank, K.M., 1992, Graptolite biostratigraphy of the Ordovician Martinsburg Formation in New Jersey and contiguous areas: New Jersey Geological Survey, Geological Survey Report 28, 18 p.

NGMDB product
Counties Sussex - Warren