PBDB Collection

Helokybe-Encrinurus-Richterarges Assemblage of the Read Bay Fm., Cornwallis Is. (Silurian of Canada)

Where: Nunavut, Canada (75.0° N, 95.0° W: paleocoordinates 0.8° N, 30.5° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: A Member (Read Bay Formation), Ludlow (427.4 - 423.0 Ma)

• member-level stratigraphic resolution

Environment/lithology: shallow subtidal; calcareous lime mudstone and wackestone

• "Level-bottom carbonate shelf...BA 2, shallow marine subtidal. The fossils are generally undamaged and articulated. The sessile and sedentary brachiopods, bryozoans, corals, calcareous algae, and stromatoporoids occur in life position...Further the numerous corals and pelmatozoans suggest a subtidal environment, and shallow marine conditions are also indicated the abundant Atrypoidea and leperditiid ostracodes. Thin beds of shelly and intraclastic packstone (with scoured based) ...present at irregular intervals. [Strata probably] deposited between wave base and storm wave base."

•SEP environmental call based on given info.

• "Most of the trilobites were found in highly fossiliferous calcareous mudstones and wackestones, in which traction current structures are very rare."

Primary reference: A. T. Thomas and P. D. Lane. 1999. Trilobite assemblages of the North Atlantic Region. in A. J. Boucot and J. D. Lawson, eds. Paleocommunities--a case study from the Silurian and Lower Devonian. Cambridge University Press, Cambrdige 444-457. [M. Foote/M. Foote/M. Foote]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 23082: authorized by Michael Foote, entered by Michael Foote on 09.07.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names

Rhodophyceae
- Solenoporaceae	Solenopora sp. Solenopora sp. Dybowski 1877 calcareous algae
Chlorophyceae
- Receptaculitidae	Ischadites sp. Ischadites sp. Eichwald 1861 calcareous algae
Stromatoporoidea
Stromatoporoidea -	Stromatoporoidea indet. Stromatoporoidea indet. stromatoporoid sponge
Anthozoa
Favositida - Coenitidae	Coenites sp. Coenites sp. Eichwald 1829 tabulate coral
Favositida - Favositidae	Favosites sp. Favosites sp. Lamarck 1816 tabulate coral
Auloporida - Syringoporidae	Syringopora sp. Syringopora sp. Goldfuss 1826 tabulate coral
Rugosa -	Rugosa indet. Rugosa indet. horn coral solitary rugosans
Stauriida - Mucophyllidae	Mucophyllidae indet. Mucophyllidae indet. Soshkina 1947 horn coral mucophyllids
unclassified
-	Echinodermata indet. Echinodermata indet. Klein 1754 pelmatozoans
Bivalvia
-	"Pelecypoda indet." = Bivalvia "Pelecypoda indet." = Bivalvia Linnaeus 1758 clam
Gastropoda
-	Gastropoda indet. Gastropoda indet. Cuvier 1795 snail
Cephalopoda
Nautiloidea -	Nautiloidea indet. Nautiloidea indet. Agassiz 1847 nautiloid orthocones
Rhynchonellata
Pentamerida - Gypidulidae	Gypidula sp. Gypidula sp. Hall 1867
Spiriferida - Spinocyrtiidae	Orthospirifer sp. Orthospirifer sp. Pitrat 1975 genus name in quotes
Spiriferida - Delthyrididae	Howellella sp. Howellella sp. Kozlowski 1946
Atrypida - Atrypidae	Atrypa sp. Atrypa sp. Dalman 1828
Atrypida - Septatrypidae	Atrypoidea sp. Atrypoidea sp. Mitchell and Dun 1920
Rhynchonellida - Rhynchotrematidae	Stegerhynchus sp. Stegerhynchus sp. Foerste 1909
Strophomenata
Orthotetida - Chilidiopsidae	Fardenia sp. Fardenia sp. Lamont 1935 genus name in quotes
Bryozoa
-	Bryozoa indet. Bryozoa indet. Ehrenberg 1831
Trilobita
Corynexochida - Styginidae	Styginidae indet. Styginidae indet. Vogdes 1890 trilobite effaced styginids
Lichida - Lichidae	Richterarges spp. Richterarges spp. Phleger 1936 trilobite
Proetida - Proetidae	Helokybe spio Helokybe spio Thomas and Narbonne 1979 trilobite
Proetida - Otarionidae	Cyphaspis sp. Cyphaspis sp. Burmeister 1843 trilobite
Phacopida - Encrinuridae	Encrinurus sp., ? Kailia sp. Encrinurus sp. Emmrich 1844 trilobite ? Kailia sp. Chang 1974 trilobite
Ostracoda
Leperditicopida - Leperditiidae	Leperditia sp. Leperditia sp. Rouault 1851 ostracod