The Shawangunk is defined as a light to dark-gray, fine to very coarse grained sandstone and conglomerate, containing a few shale interbeds.[3] There are also four members of this formation: Tammany, Lizard Creek, Minsi, and Weiders.
The Lizard Creek member is described at Lehigh Gap as having conglomerates, sandstone, calcareous sandstone, siltstone, and shale with a few minor red beds. The Minsi Member is described as a conglomeritic quartzite and the Weiders is described as both a conglomerate and quartzite.[4] The Tammany and Lizard Creek members are equivalent to the Clinton Formation and the Minsi and Weiders members are equivalent to the Tuscarora Formation in the central and western part of Pennsylvania. The Tammany Member was not described at Lehigh Gap.[3]
The depositional environment of the Shawangunk has always been interpreted as mostly terrestrial to a shallow marine deposit resulting in a molasse sequence produced by the Taconic orogeny. The numerous coarse-grained beds, especially in the lower part, suggest a relatively close orogenic source with very high to high energy fluvial systems depositing the sediments. Shale interbeds may indicate a slowing or shifting of these ancient river systems.[4]
Very few fossils exist in the Shawangunk; however, Eurypterids can be found in the middle portions of the formation roughly 420–750 feet from the base in some locations in New York State.[5] Linguloid brachiopods were identified in the Lizard Creek Member.[1]
The hardness of the quartzite and conglomerate layers make the Shawangunk an excellent building stone. Some of the boulders that have accumulated as colluvium at the base of Blue Mountain are used for decorative stone, building stone, and aggregate.[4]
^ abcEpstein, J.B., and Epstein, A.G., 1972, The Shawangunk Formation (Upper Ordovician (?) to Middle Silurian) in eastern Pennsylvania: U.S. Geological Survey Professional Paper 744, 45 p. [1]
^Mather, W.W., 1840, Fourth annual report of the first geological district of the State of New York: New York Geological Survey Annual Report, no. 4, p. 209-258.
^ abcdEpstein, J.B., Sevon, W.D., Glaeser, J.D. (1974). Geology and the Mineral Resources of the Lehighton and Palmerton Quardrangles, Carbon and Northampton Counties, Pennsylvania. The Pennsylvania Geologic Survey, Harrisburg, PA. A195c&d.
^Epstein, J.B., (1993) Stratigraphy of Silurian Rocks in Shawangunk Mountain, Southeastern New York, Including a Historical Review of Nomenclature. United States Geological Survey Publication L14.
^Berg, T.M., et al., (1983). Stratagraphic Correlation Chart of Pennsylvania: G75, Pennsylvania Geologic Survey, Harrisburg, Pennsylvania.
