The Feltville Formation is a mapped bedrock unit primarily in

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

, with one known

outlier In statistics, an outlier is a data point that differs significantly from other observations. An outlier may be due to a variability in the measurement, an indication of novel data, or it may be the result of experimental error; the latter are ...

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

and another one in

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

. It is named for the Deserted Village of Feltville in Watchung Reservation, 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 Oakland is a borough in Bergen County, in the U.S. state of New Jersey and a suburb of New York City. As of the 2020 United States census, the borough's population was 12,748, a decrease of six people from the 2010 census count of 12,754, whi ...

Depositional environment

The Feltville Formation can be characterized as a continuation of the Passaic Formation, 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 Semi-arid climate, semiar ...

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 (continent), Siberia during the Carboniferous period ...

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

ornithischian Ornithischia () is an extinct clade 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 The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triass ...

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 of the United States Mudstone formations of the United States Alluvial deposits Ichnofossiliferous formations Paleontology in New Jersey Paleontology in New York (state) Paleontology in Pennsylvania Limestone formations of the United States