Grinshill quarries (Triassic of the United Kingdom)

Also known as Greensell

Where: England, United Kingdom (52.8° N, 2.7° W: paleocoordinates 15.6° N, 10.5° E)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Tarporley Siltstone Formation (Mercia Mudstone Group), Anisian (247.2 - 242.0 Ma)

• "The Tarporley Siltstone Formation, typically ranging from 20 to 250 m in thickness (Warrington et al. 1980, table 4), is only about 6-10 m thick at Grinshill" (Benton & Spencer 1995). Some Rhynchosaurus remains may also come from the underlying Helsby Sandstone Formation.

•Tarporley Siltstone formerly known as "Waterstones"; Helsby Sandstone formerly known as "Ruyton & Grinshill Sandstones" or the "Building Stones"

•Palynological data indicates an Anisian age (Benton et al. 1994)

• group of beds-level stratigraphic resolution

Environment/lithology: paralic; fine-grained, micaceous, gray sandstone and coarse-grained, gray, red sandstone

• "Thompson (1985) interprets the overall sedimentary regime of these two facies as 'tropical arid belt fluvial and marine marginal hyprsalaine lagoon (salina) deposits '. [...] 'The environment was probably fluvial-intertidal rather than lake marginal. '" (Benton, 1990)
• The R. articeps specimens occur in two major sediment types, as noted by Owen (1842 b, p. 146): a fine-grained grey sandstone [...] and a coarser pinkish-grey sandstone termed by him' burr-stone' [...]. The fine sandstone is grey to beige in colour and has subrounded sand grains with greenish mud flakes and specks of mica and manganese. The slabs show fine parallel lamination and the horizontal surfaces may show evidence of ripple marks as well as irregular lumps up to 10 mm in diameter." (Benton, 1990)

Size class: macrofossils

Preservation: cast, trace

Reposited in the BMNH

Collection methods: quarrying, surface (in situ), mechanical,

• SHRBM: Shrewsbury Borough Museum

•SCRCM: Shropshire County Museum, Ludlow

•MANCH: Manchester Museum

•BATGM: Bath Geology Museum

•WARMS: Warwickshire Museum, Warwick

•BGS: British Geological Survey Museum, Keyworth

Primary reference: R. Owen. 1842. Description of an Extinct Lacertilian Reptile, Rhynchosaurus articeps, Owen, of which the Bones and Foot-prints characterize the Upper New Red Sandstone at Grinshill, near Shrewsbury. Transactions of the Cambridge Philosophical Society 7(3):355-369 [J. Mueller/T. Liebrecht]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 80838: authorized by Johannes Mueller, entered by Jana Dummasch on 14.05.2008, edited by Torsten Liebrecht, Richard Butler and Bethany Allen

Creative Commons license: CC BY (attribution)

Taxonomic list

• "About 17 individuals of R. articeps have been collected from Grinshill, but some specimens have been missing since the 19th century, and the total could be greater. The minimum number of individuals (MNI), estimated on the basis of the number of skulls, is 7." (Benton, 1990)
Reptilia
  - Rhynchosauroidae
Rhynchosauroides sp.1 Maidwell 1911 reptile
23 slabs in SHRBM, MANCH, WARMS, BGS, BuGD collections
 Eosuchia - Rhynchosauridae
Rhynchosaurus articeps n. gen. n. sp.
Rhynchosaurus articeps n. gen. n. sp. Owen 1842 rhynchosaur
SHRBM G132/1982 (formerly ShM 1, lectotype). G134/1982 (formerly ShM 2, paralectotype), G133/1982+G151/1982 (formerly ShM 4); SHRBM 3, 5, 6, 7; BMNH R1236 to R1240; BATGM M20a, b; MANCH L7642; SHRCM G3851; 2 unnumbered specimens from Keele University
 Pseudosuchia - Chirotheriidae
Isochirotherium sp.2 Haubold 1971 archosaur
SHRBM G194/1982; LIVCM 45.25.HH?
Chirotherium sp.1 Kaup 1835 archosaur
2 slabs, SHRBM, SHRCM collections