Portland

302 occ. 58 taxons (8 genres) 1 pays

Description

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 and the floodplain of a river. 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 to the late Hettangian and Sinemurian ages.

Description en anglais — traduction française non disponible.

Genres

8 genres

Eubrontes

Dinosaures

Valide Ichnogenre 9 occ. · 250 Ma

Platypterna

Dinosaures

Valide Ichnogenre Taxon formel 3 occ. · 227 Ma

Anomoepus

Dinosaures

Valide Ichnogenre 3 occ. · 237 Ma

Plectropterna

Dinosaures

Valide Ichnogenre Taxon formel 2 occ. · 201 Ma

Grallator

Dinosaures

Valide Ichnogenre 2 occ. · 250 Ma

Plesiornis

Dinosaures

Valide Ichnogenre Taxon formel 1 occ. · 227 Ma

Anchisaurus

Dinosaures

Valide 1 occ. · 201 Ma

Anchisauripus

Dinosaures

Valide Ichnogenre Taxon formel 1 occ. · 247 Ma

cliquer pour agrandir

Original figure caption: .mw-parser-output .smallcaps{font-variant:small-caps}The Middletown Slab covered with the Footprints of Carnivorous Dinosaurs. The tracks are in high relief. Additional notes: Most if not all of these tridactylous (i.e. three-toed) footprints/tracks (but not the actual trackmaker!) are referred to as Grallator or as Grallator-type trace fossils. “High relief” means that these are actually casts of footprints forming a positive relief on the lower surface of the sandstone slab (so-called positive hyporelief). The material that originally formed the mud over which the dinosaurs walked was too friable to be recovered from the quarry in one piece. The slab consists of so called ‘brownstone’ which is the trading name of the sandstone quarried at Middletown, Connecticut. This sandstone belongs to the Lower Jurassic Portland Formation of the Hartford Basin (“Connecticut Valley”) and thus to the upper part of the Newark Supergroup. The trackmakers probably were relatively small ‘primitive’ theropod dinosaurs (coelophysoids) such as Podokesaurus the remains of which were recovered from Lower Jurassic deposits of the Hartford Basin. © Richard S. Lull · Public domain · Wikipedia

Plage temporelle

Trias

Jurassique

Crétacé

Paléogène

Néogène

252 201 145 66 0 Ma

Groupe géologique / Membre

Agawam 302

Principaux pays

🇺🇸 États-Unis 302

Environnements de dépôt

Fluvio-lacustre indéterminé 204

Terrestre indéterminé 66

Lac de petite taille 32

Principaux collecteurs

E. Hitchcock 125

D. Marsh 100

Hitchcock 46

J. Deane 33

H. Hammer 27

Marsh 26

Deane 20

J. Bryant 17

P. Moody 14

W. Clark 11

J. Barratt 6

W. Gringras 4

Activité de collecte par décennie

1800s 14

1810s 1

1830s 66

1840s 34

1850s 70

1860s 14

1870s 1

1880s 4

1900s 6

1910s 1

1930s 2

1960s 4