Portland Formation facts for kids

Quick facts for kids Portland Formation Stratigraphic range: Hettangian-Sinemurian ~199–195Ma PreЄ Є O S D C P T J K Pg N ↓
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 / 42.3; -72.5
Approximate paleocoordinates	24°00′N 18°36′W / 24.0°N 18.6°W / 24.0; -18.6
Region	Connecticut, Massachusetts
Country	USA
Extent	Deerfield & Hartford Basins

The Portland Formation is a geological formation in Connecticut and Massachusetts in the northeastern United States. It dates back to the Early Jurassic period. 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).

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.

Vertebrate paleofauna

Dinosaur coprolites located in Massachusetts, USA. Ornithischian tracks located in Massachusetts and Connecticut, USA. Theropod tracks located in Massachusetts and Connecticut, USA. Prosauropod tracks located in Massachusetts and Connecticut, USA.

Dinosaurs
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Anchisaurus	A. polyzelus	Connecticut Massachusetts
Podokesaurus	P. holyokensis	Connecticut		Partial postcranial skeleton.	All known remains of this species have been destroyed.