Breadstone shaft (Ordovician of the United Kingdom)

Where: United Kingdom (51.7° N, 2.4° W: paleocoordinates 74.6° S, 19.4° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Breadstone Shales Formation, Tremadocian (485.4 - 477.7 Ma)

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified, micaceous, gray, blue shale

• The shales are micaceous and for the most part soft and fissile, breaking with a conchoidal to platy fracture. They are generally of a grey or bluish grey colour weathering buff, but in some places are slightly red-stained, undoubtedly deriving this colour from the once overlying Trias. Their joint faces are often coated

•with iron oxide. Harder beds occur, and there are bands and pockets of a more sandy nature. On the other hand, the Breadstone shaft passes through two bands of particularly dark soft shale which show a considerable amount of slickensiding.

•The bands are several feet thick and about twenty feet apart. Among the debris filling the shaft were fragments of a thin bed of limestone between two and three inches in thickness in which a cone-in-cone structure was strongly developed.

Size classes: macrofossils, mesofossils

Preservation: mold/impression

Collected by S. Smith in 1932

Primary reference: S. Smith and C. J. Stubblefield. 1933. On the occurrence of Tremadoc shales in the Tortworth Inlier (Gloucestershire), with notes of the fossils. Quarterly Journal of the Geological Society of London 89:357-378 [M. Hopkins/M. Hopkins]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 208218: authorized by Melanie Hopkins, entered by Melanie Hopkins on 24.03.2020

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Trilobita
 Asaphida - Asaphidae
Niobella (Niobe) homfrayi smithi
Pterobranchia
 Dendroidea - Acanthograptidae
Dictyonema sp.
Dictyonema sp. Hall 1851 graptolite
Ostracoda
 Palaeocopida - Primitiidae
cf. Primitia ostrogothica
  -
Septadella jackmanae n. gen. n. sp.
Septadella jackmanae n. gen. n. sp. Smith and Stubblefield 1933 ostracod
Artiopoda
 Agnostida - Agnostidae
"Agnostus calvus" = Micragnostus calvus
"Agnostus calvus" = Micragnostus calvus Lake 1906
Trilobita
 Ptychopariida - Shumardiidae
Shumardia sp.
Shumardia sp. Billings 1862 trilobite
 Olenida - Olenidae
"Beltella depressa" = Leptoplastides depressus
"Beltella depressa" = Leptoplastides depressus Salter In Murchinson 1859 trilobite
Gastropoda
 Bellerophontida - Bellerophontidae
Bellerophon sp.
Bellerophon sp. de Montfort 1808 snail
Hyolitha
 Hyolithida - Hyolithidae
Hyolithes cf. aratus
Lingulata
 Acrotretida - Acrotretidae
Acrotreta sp., Acrotreta cf. sabrinae
Acrotreta sp. Kutorga 1848
 Lingulida - Obolidae
Lingulella cf. lepis, Lingulella sp.
Lingulella sp. Salter 1866