Berkshire Valley and Poxono Island Formations, undivided (NJSbp;6)

Berkshire Valley and Poxono Island Formations, undivided - Thickness ranges from 76 m (250 ft) at Greenwood Lake to 122 m (400 ft) in Longwood Valley. Berkshire Valley Formation (Barnett, 1970) - Commonly yellowish-gray weathering, medium-gray to pinkish-gray, very thin to thin-bedded fossiliferous limestone interbedded with gray to greenish-gray calcareous siltstone and silty dolomite, medium-gray to light-gray dolomite conglomerate, and grayish-black, thinly laminated shale. Lower contact conformable. Thickness ranges from 27 to 38 m (90-125 ft) thick. Poxono Island Formation, (White, 1882; Barnett, 1970) - Very thin to medium-bedded sequence of medium-gray, greenish-gray, or yellowish-gray, mud-cracked dolomite; light-green, pitted, medium-grained calcareous sandstone, siltstone, and edgewise conglomerate containing gray dolomite; and quartz-pebble conglomerate containing angular to subangular pebbles as much as 2 cm (0.8 in.) long. Interbedded grayish-green shales at lower contact are transitional into underlying Longwood Shale. Thickness ranges from 49 to 84 m (160-275 ft) thick.

State	New Jersey
Name	Berkshire Valley and Poxono Island Formations, undivided
Geologic age	Upper Silurian
Original map label	Sbp
Primary rock type	limestone
Secondary rock type	dolostone (dolomite)
Other rock types	conglomerate; siltstone; shale; sandstone
Lithologic constituents	Major Sedimentary > Carbonate > Limestone (Bed)Berkshire Valley Formation - Commonly yellowish-gray weathering, medium-gray to pinkish-gray, very thin to thin-bedded fossiliferous limestone. Minor Sedimentary > Clastic > Sandstone (Bed)Poxono Island Formation - light-green, pitted, medium-grained calcareous sandstone. Sedimentary > Clastic > Mudstone > Shale (Bed)Berkshire Valley Formation - grayish-black, thinly laminated shale. Poxono Island Formation - interbedded grayish-green shales at lower contact are transitional into underlying Longwood Shale. Sedimentary > Clastic > Conglomerate (Bed)Berkshire Valley Formation - medium-gray to light-gray dolomite conglomerate. Poxono Island Formation - edgewise conglomerate containing gray dolomite; and quartz-pebble conglomerate containing angular to subangular pebbles as much as 2 cm (0.8 in.) long. Sedimentary > Carbonate > Dolostone (Bed)Berkshire Valley Formation - silty dolomite, medium-gray to light-gray dolomite conglomerate. Poxono Island Formation - ery thin to medium-bedded sequence of medium-gray, greenish-gray, or yellowish-gray, mud-cracked dolomite. Sedimentary > Clastic > Siltstone (Bed)Berkshire Valley Formation - interbedded with gray to greenish-gray calcareous siltstone and silty dolomite. Poxono Island Formation - siltstone
Map references	Dalton, R. F., Herman, G. C., Monteverde, D. H., Pristas, R. S., Sugarman, P. J., 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) export file: geology.e00, scale 1:100,000, unit description files: cslegend.pdf and nlegend.pdf, metadata: metast.pdf.
Unit references	Dalton, R. F., Herman, G. C., Monteverde, D. H., Pristas, R. S., Sugarman, P. J., 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) export file: geology.e00, scale 1:100,000, unit description files: cslegend.pdf and nlegend.pdf, metadata: metast.pdf. 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, scale 1 to 100,000, 4 cross sections, 2 sheets, size 56x40; 58x41. [http://pubs.er.usgs.gov/publication/i2540A] White, I.C., 1882, The geology of Pike and Monroe Counties: Pennsylvania Geological Survey, 2nd series, Report G-6, 407 p. Barnett, S.G., III, 1970, Upper Cayugan and Helderbergian stratigraphy of southeastern New York and northern New Jersey: Geological Society of America Bulletin, v. 81, no. 8, p. 2375-2402.
Geographic coverage	Morris - Passaic