Earth:Portland Formation
| Portland Formation Stratigraphic range: Hettangian-Sinemurian ~199–195 Ma | |
|---|---|
| Type | Geological formation |
| Unit of | Newark Supergroup |
| Sub-units | Turners Falls Sandstone & Mount Toby Formation |
| Lithology | |
| Primary | Sandstone |
| Other | Mudstone, siltstone, limestone |
| Location | |
| Coordinates | [ ⚑ ] : 42°18′N 72°30′W / 42.3°N 72.5°W |
| Paleocoordinates | [ ⚑ ] 24°00′N 18°36′W / 24.0°N 18.6°W |
| Region | Connecticut, Massachusetts |
| Country |  USA |
| Extent | Deerfield & Hartford Basins |
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The Portland Formation is a geological formation in Connecticut and Massachusetts in the northeastern United States.[1] It dates back to the Early Jurassic period.[2] The formation consists mainly of sandstone laid down by a series of lakes (in the older half of the formation) and the floodplain of a river (in the younger half). The sedimentary rock layers representing the entire Portland Formation are over 4 kilometres (2.5 mi) thick and were formed over about 4 million years of time, from the Hettangian age (lower half) to the late Hettangian and Sinemurian ages (upper half).[3]
In 2016, the paleontologist Robert E. Weems and colleagues suggested the Portland Formation should be elevated to a geological group within the Newark Supergroup (as the Portland Group), and thereby replacing the former name "Agawam Group". They also reinstated the Longmeadow Sandstone as a formation (within the uppermost Portland Group); it had earlier been considered identical to the Portland Formation.[4]
Vertebrate paleofauna
Dinosaur coprolites are located in Massachusetts, USA.[2] Ornithischian tracks, Theropod tracks and Sauropodomorph tracks are located in Massachusetts and Connecticut, USA.[2]
| Dinosaurs | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Anchisaurus[2] | A. polyzelus[2] |  | ||||
| Podokesaurus[2] | P. holyokensis | Massachusetts | Partial postcranial skeleton.[5] | All known remains of this species have been destroyed.[citation needed] |  | |
| Neotheropoda sp.[6] | Massachusetts | Partial humerus. | Estimated to have been 9 meters long. | |||
| Non-Dinosaur Archosaurs | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| S. longipes | Hine's Quarry, Longmeadow | Partial postcranial skeleton. | Originally Stegomus. | _(18125938496).jpg) | ||
| Pterosauria sp.[7] | South Hadley, Massachusetts | Partial Wrist and tooth. | Non-pteradactyloid pterosaur estimated to have a wingspan of 40 cm. | |||
See also
- List of dinosaur-bearing rock formations
References
- ↑ Portland Formation - USGS
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Weishampel et al., 2004, pp.530–532
- ↑ Olsen, P.E. (2002). "Stratigraphy and Age of the Early Jurassic Portland Formation of Connecticut and Massachusetts: A Contribution to the Time Scale of the Early Jurassic". https://gsa.confex.com/gsa/2002NE/finalprogram/abstract_31961.htm.
- ↑ Weems, R. E.; Tanner, L. H.; Lucas, S. G. (2016). "Synthesis and revision of the lithostratigraphic groups and formations in the Upper Permian?–Lower Jurassic Newark Supergroup of eastern North America". Stratigraphy 13 (2): 111–153. https://pubs.er.usgs.gov/publication/70188433.
- ↑ "Table 3.1," in Weishampel et al., 2004, p.48
- ↑ McMenamin, M. (2021). Large neotheropod from the Lower Jurassic of Massachusetts. AcademiaLetters, Article 3591. doi:10.20935/AL3591.1©2021 by the author — Open Access — Distributed under CC BY 4.0
- ↑ https://www.researchgate.net/publication/355340350_Early_Jurassic_pterosaur_from_Massachusetts
Bibliography
- Weishampel, David B., ed (2004). The Dinosauria, 2nd edition. Berkeley: University of California Press. ISBN 0-520-24209-2. https://books.google.com/books?id=vtZFDb_iw40C. Retrieved 2019-02-21.
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