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The Upper Greensand Formation is a Cretaceous formation of Albian to Cenomanian in age, found within the Wessex Basin and parts of the Weald Basin in southern England. [1] It overlies the Gault Clay and underlies the Chalk Group. It varies in thickness from zero to 75 m. It is predominantly a glauconitic fine-grained sandstone, locally becoming ...
The Allegheny Group, often termed the Allegheny Formation, [2] is a Pennsylvanian-age geological unit in the Appalachian Plateau. It is a major coal -bearing unit in the eastern United States , extending through western and central Pennsylvania , western Maryland and West Virginia , and southeastern Ohio .
Stratigraphically above the Lower Greensand Group is the Selborne Group which comprises a suite of mudstones, siltstones, sandstones and limestones laid down during the Albian age between 112 and 94 million years ago. It divides into an earlier Gault Formation and a later Upper Greensand Formation.
Overlying the Lower Greensand are the two formations which comprise the Selborne Group; the Albian age Gault Formation and the Upper Greensand Formation which extends from the Albian into the Cenomanian (c.100.5-94 Ma) thereby straddling the boundary with the Late Cretaceous epoch.
The Permian Dunkard Group (Pd) is an area of rock, Early Permian in age, in the south of Ohio, southwestern Pennsylvania, West Virginia and the hilltops of the Georges Creek Basin of Maryland. [2] In Ohio, it is found primarily in Washington County. It is notable for being one of the few areas of Permian sediment east of the Mississippi River ...
The Allegheny River (/ ˌ æ l ɪ ˈ ɡ eɪ n i / AL-ig-AY-nee) is a 325-mile-long (523 km) tributary of the Ohio River that is located in western Pennsylvania and New York in the United States.
A distinction is made between the Upper Greensand and Lower Greensand. The term greensand was originally applied by William Smith to glauconitic sandstones in the west of England and subsequently used for the similar deposits of the Weald, before it was appreciated that the latter are actually two distinct formations separated by the Gault Clay ...
(The Shawngunk Formation) This combination of depositional features means that the source area was relatively close and deposited in a moist climate. These sediments grade into finer reddish sands and silts, (Bloomsburg Formation) as the source area became more distant and/or less productive. The climate during this time was drier. [2]