The Feltville Formation is a mapped bedrock unit primarily in

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

, with one known outlier in

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

and another one in New York. It is named for the Deserted Village of Feltville in

Watchung Reservation Watchung Reservation is the largest nature reserve in Union County, New Jersey, United States. Covering 1,945 acres, it is bounded by the city of Summit, the borough of Mountainside, and the townships of Berkeley Heights, Scotch Plains, and ...

, New Jersey, which is near where its type section was described by paleontologist Paul E. Olsen.

Description

The Feltville Formation is composed of red, gray, and white sandstone of varying grain thickness, as well as red, gray, and black siltstone and calcareous mudstone. Sandstone/siltstone layers tend to be alternatingly massive and cross-bedded. Black to white carbonaceous limestone layers exist near the base of the formation.Mineral Resources Online Spatial Data – Feltville Formation, New Jersey
U.S. Geological Survey. Accessed July 23, 2010. Additionally, pebbles and cobbles of quartz are embedded within layers of sandstone and siltstone that interfinger with the Feltville Formation near Oakland, New Jersey.

Depositional environment

The Feltville Formation can be characterized as a continuation of the

Passaic Formation The Passaic Formation is a mapped bedrock unit in Pennsylvania, New Jersey, and New York. It was previously known as the Brunswick Formation since it was first described in the vicinity of New Brunswick, New Jersey. It is now named for the city of ...

, which is mostly playa and

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but a ...

deposits resulting from the rifting of

Pangea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...

. The primarily red color of this formation is often evidence that the sediments were deposited in arid conditions.Faill, R.T., (2004). The Birdsboro Basin. ''Pennsylvania Geology'' V. 34 n. 4. However, the Feltville Formation differs from the Passaic Formation in that it contains a more significant portion of non-red layers, which were laid down by deep lakes present during wetter periods.Schlische, Roy W.
Geology of the Newark Rift Basin
Department of Geological Sciences, Rutgers University, Piscataway, NJ. Accessed July 23, 2010.

Fossils

Fish fossils, commonly those of the ray-finned ''

Semionotus ''Semionotus'' (from el, σημιον , 'mark' and el, νῶτος , 'back') is an extinct genus of ray-finned fish found throughout Northern Pangaea ( North America and Europe) during the late Triassic, becoming extinct in the Early Jurassic ...

'', can be found in limestone layers within the formation. In other layers, indeterminate fossil

ornithischian Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek st ...

tracks have been noted,Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607. along with additional reptile and dinosaur prints. Fossil plant remains, as well as root structures and pollen, are also found in the formation.

Age

The Feltville Formation rests conformably above the Orange Mountain Basalt and below the Preakness Basalt, placing its deposition somewhere between approximately 199 and 196 million years ago during the early Jurassic stage known as the Hettangian.

Economic geology

The Feltville Formation was once mined for freestone, as indicated by a historical work detailing quarrying operations at the base of Preakness Mountain in New Jersey.Gordon, Thomas Francis. A Gazetteer of the State of New Jersey – Comprehending a General View of its Physical and Moral Condition, together with a Topographical and Statistical Account of its Counties, Towns, Villages, Canals, Railroads, &c. Published by D. Fenton, 1834.
Available via Google Books
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References

Bibliography

* {{Geology of the Newark Basin Geologic formations of New Jersey Geologic formations of New York (state) Geologic formations of Pennsylvania Hettangian Stage Jurassic geology of New Jersey Sandstone formations of the United States Siltstone formations Mudstone formations Alluvial deposits Ichnofossiliferous formations Paleontology in New Jersey Paleontology in New York (state) Paleontology in Pennsylvania