Portland Formation
Portland Formation Stratigraphic range: Hettangian-Sinemurian ~199–195 Ma | |
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Type | Geological formation |
Unit of | Newark Supergroup |
Sub-units | & Mount Toby Formation |
Lithology | |
Primary | Sandstone |
Other | Mudstone, siltstone, limestone |
Location | |
Coordinates | 42°18′N 72°30′W / 42.3°N 72.5°WCoordinates: 42°18′N 72°30′W / 42.3°N 72.5°W |
Approximate paleocoordinates | 24°00′N 18°36′W / 24.0°N 18.6°W |
Region | Connecticut, Massachusetts |
Country | ![]() |
Extent | & Hartford Basins |
![]() ![]() Portland Formation (the United States) |
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 Prosauropod tracks are located in Massachusetts and Connecticut, USA.[2]
Dinosaurs | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
Anchisaurus[2] | A. polyzelus[2] | ![]() | ||||
Podokesaurus[2] | P. holyokensis | Connecticut[2] | Partial postcranial skeleton.[5] | All known remains of this species have been destroyed.[citation needed] | ![]() |
See also[]
- List of dinosaur-bearing rock formations
References[]
- ^ Portland Formation - USGS
- ^ Jump up to: a b c d e f g h i 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". Archived from the original on 2018-11-28. Retrieved 2017-07-07.CS1 maint: bot: original URL status unknown (link). Session No. 26 Studies of Depositional Systems and Sedimentary Rocks: In Honor of Edward Scudder Belt. 37th Annual Meeting (March 25-27, 2002).
- ^ 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.
- ^ "Table 3.1," in Weishampel et al., 2004, p.48
Bibliography[]
- The Dinosauria, 2nd edition, 1–880. Berkeley: University of California Press. Accessed 2019-02-21. ISBN 0-520-24209-2 ; , and . 2004.
- Geologic formations of the United States
- Jurassic Connecticut
- Jurassic Massachusetts
- Early Jurassic North America
- Jurassic System of North America
- Sandstone formations of the United States
- Ichnofossiliferous formations