Rondout and Decker Formations, undivided (NJDSrd;7)

Rondout and Decker Formations, undivided - Rondout Formation (Clarke and Schuchert, 1899) - Upper part is medium-gray weathering, medium-dark-gray, very fine to fine-grained, medium-bedded, fossiliferous, argillaceous limestone. Middle part is light-medium-gray-weathering, medium-gray, laminated to medium-bedded, argillaceous dolomite. Locally contains deep desiccation polygons. Lower part is medium-gray-weathering, medium- to dark-gray, very fine to medium-grained, medium-bedded fossiliferous limestone. Silurian-Devonian boundary placed in middle of formation (Denkler and Harris, 1988). Lower contact abrupt and placed at top of highest calcareous quartz sandstone. Thickness approximately 12 m (40 ft). Decker Formation (White, 1882) - Light-gray- to yellowish-gray-weathering, light- to medium-gray, calcareous quartz siltstone, sandstone, and fine-pebble conglomerate locally interbedded with fossiliferous medium-gray, medium- to coarse-grained limestone and very fine grained, thin- to medium-bedded dolomite. Lower contact gradational. Thickness varies from 15 m (50 ft) near Duttonville to 25 m (82 ft) at Wallpack Center.

State	New Jersey
Name	Rondout and Decker Formations, undivided
Geologic age	Lower Devonian and Upper Silurian
Original map label	DSrd
Primary rock type	limestone
Secondary rock type	dolostone (dolomite)
Other rock types	siltstone; sandstone; conglomerate
Lithologic constituents	Major Sedimentary > Carbonate > Limestone (Bed)Rondout Formation - Upper part is medium-gray weathering, medium-dark-gray, very fine to fine-grained, medium-bedded, fossiliferous, argillaceous limestone. Lower part is medium-gray-weathering, medium- to dark-gray, very fine to medium-grained, medium-bedded fossiliferous limestone. Decker Formation - locally interbedded with fossiliferous medium-gray, medium- to coarse-grained limestone. Minor Sedimentary > Clastic > Conglomerate (Bed)Decker Formation - Light-gray- to yellowish-gray-weathering, light- to medium-gray fine-pebble conglomerate. Sedimentary > Clastic > Sandstone (Bed)Decker Formation - Light-gray- to yellowish-gray-weathering, light- to medium-gray, calcareous sandstone. Sedimentary > Clastic > Siltstone (Bed)Decker Formation - Light-gray- to yellowish-gray-weathering, light- to medium-gray, calcareous quartz siltstone. Sedimentary > Carbonate > Dolostone (Bed)Rondout Formation - middle part is light-medium-gray-weathering, medium-gray, laminated to medium-bedded, argillaceous dolomite. Decker Formation - very fine grained, thin- to medium-bedded dolomite.
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] Clarke, J.M., and Schuchert, Charles, 1899, The nomenclature of the New York series of geological formations: Science, new series, v. 10, p. 874-878. Denkler, K.E., and Harris, A.G., 1988, Conodont-based determination of the Silurian-Devonian boundary in the Valley and Ridge Province, Northern and Central Appalachians, in Sando, W.J., Contributions to paleontology and stratigraphy: U.S. Geological Survey Bulletin 1837, p. B1-B13. [http://pubs.er.usgs.gov/publication/b1837] White, I.C., 1882, The geology of Pike and Monroe Counties: Pennsylvania Geological Survey, 2nd series, Report G-6, 407 p.
Geographic coverage	Sussex