The Ermaying Formation is a sedimentary succession of

Anisian In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...

(

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...

) age. It is found in the

Shaanxi Province Shaanxi (alternatively Shensi, see § Name) is a landlocked province of China. Officially part of Northwest China, it borders the province-level divisions of Shanxi (NE, E), Henan (E), Hubei (SE), Chongqing (S), Sichuan (SW), Gansu (W), Ningx ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. It is composed of an up to 600 m thick sequence of

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

and

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

. It is famous for its fossils of

tetrapods Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct therapsids ...

Fossil content

Notable fossils include the genera ''

Fenhosuchus ''Fenhosuchus'' is an extinct genus of archosauriform. The holotype, IVPP V 2697, and referred materials have been found in the Hsishihwa locality at Wuhsiang, China, from the Upper Ermaying Formation (also Ehrmaying). The locality dates bac ...

Eumetabolodon ''Eumetabolodon'' is an extinct genus of procolophonine procolophonid parareptile from early and middle Triassic (Induan to earliest Anisian stages) deposits of Nei Mongol, northern China. Two species of ''Eumetabolodon'' were named by J. L. L ...

Halazhaisuchus ''Halazhaisuchus'' is an extinct genus of archosauriform from the Early Triassic of China. It is known from a single species, ''Halazhaisuchus qiaoensis'', which was named in 1982 from the lower Ermaying Formation in Shaanxi. It was assigned to ...

Guchengosuchus ''Guchengosuchus'' is an extinct genus of erythrosuchid archosauriform from the Early Triassic of China. It is known from a single holotype skeleton called IVPP V 8808, described in 1991 from the lower Ermaying Formation in Shanxi. The lower Erma ...

, Neoprocolophon,

Ordosiodon ''Ordosiodon'' is an extinct genus of therocephalian therapsids from the Early Triassic of China. It includes two species, ''O. lincheyuensis'' and ''O. youngi''. ''O. lincheyuensis'', the type species, was named by Chinese paleontologist C. C. ...

Wangisuchus ''Wangisuchus'' is an extinct genus of archosauriform reptile from the Middle Triassic of China that is known from fragmentary fossil jaw bones. These bones were found at the Hsishihwa locality in the upper Ermaying Formation, which dates to the ...

'' and '' Shansisuchus.''

References

{{Reflist Geologic formations of China Triassic System of Asia Triassic China Anisian Stage Mudstone formations Sandstone formations Tuff formations Fossiliferous stratigraphic units of Asia Paleontology in Shaanxi Paleontology in Shanxi Paleontology in Inner Mongolia