Skunnemunk Conglomerate

(Darton, 1894) - Grayish-purple to grayish-red, thin- to very thick bedded, locally cross-bedded, polymictic conglomerate and sandstone containing clasts of white vein quartz, red and green quartzite and sandstone, red and gray chert, and red shale; interbedded with medium-gray, thin-bedded sandstone and greenish-gray and grayish-red, mud-cracked shale. Conglomerate and sandstone matrix is primarily hematite and microcrystalline quartz. Conglomerate cobbles range to 16.5 cm (6.5 in) long, and average cobble size increases in upper part of unit. Lower contact conformable and gradational as defined by Kummel and Weller (1902). About 915 m (3,000 ft) thick.
State New Jersey
Name Skunnemunk Conglomerate
Geologic age Middle Devonian
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone (Bed)Grayish-purple to grayish-red, thin- to very thick bedded, locally cross-bedded, polymictic conglomerate and sandstone containing clasts of white vein quartz, red and green quartzite and sandstone, red and gray chert, and red shale; interbedded with medium-gray, thin-bedded sandstone. Conglomerate and sandstone matrix is primarily hematite and microcrystalline quartz.
Sedimentary > Clastic > Conglomerate (Bed)Grayish-purple to grayish-red, thin- to very thick bedded, locally cross-bedded, polymictic conglomerate and sandstone containing clasts of white vein quartz, red and green quartzite and sandstone, red and gray chert, and red shale; Conglomerate and sandstone matrix is primarily hematite and microcrystalline quartz. Conglomerate cobbles range to 16.5 cm (6.5 in) long, and average cobble size increases in upper part of unit.
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)red shale and mud-cracked shale
Incidental
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Sedimentary > Chemical > Chert (Bed)
References

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.

https://pubs.er.usgs.gov/publication/i2540A

Darton, N.H., 1894, Geologic relations from Green Pond, New Jersey, to Skunnemunk Mountain, New York: Geological Society of America Bulletin, v. 5, p. 367-394.

Kmmel, H.B., and Weller, Stuart, 1902, The rocks of the Green Pond Mountain region: New Jersey Geological Survey Annual Report 1901, p. 1-51.

NGMDB product
Counties Passaic