Doswell Formation

The Doswell Formation was originally named to refer to a geological sequence which forms the lower part of the sedimentary fill of the Taylorsville Basin in Virginia and Maryland.

[1] A 2016 study argued that several geological layers in Pennsylvania as well as the neighboring Richmond Basin of Virginia also qualified as components of the Doswell Formation.

The Doswell formation is biostratigraphically characterized by a fauna including the fish Dictyopyge macrurus[3] and the conchostracan Laxitextella multireticulata.

[3] The Taylorsville Basin is much more restricted in terms of fossil locales, but it was home to the unusual armored reptile Doswellia.

It is believed to belong to the early Carnian (Cordevolian) age of the Triassic based on its fauna and flora,[4][2] which is distinctly dominated by tetrapods similar to gondwanan groups, as well as a high diversity of humidity-loving plants such as ferns and cycads.

The oldest of these (middle Carnian in age) was the Stagg Creek Member, a fluvial (river) deposit of sandstone and conglomerate.

This allowed the Falling Creek Member to contain a variety of rock types, including sandstone, shale, siltstone, and occasionally even coal.

In addition, it is the most fossiliferous part of the Taylorsville basin, containing the fossils of not only fish and invertebrates, but also reptiles such as the heavily armored Doswellia.

[1] In 2016, several paleontologists and geologists cooperated in a project which meant to correlate the individual Triassic basins of the Newark Supergroup with each other.

As a result, they abandoned the designation of the South Anna Formation, synonymizing it with the Stagg Creek Member as originally considered in 1980.