Locality 43, zone A (Ordovician to of Canada)

Where: Northwest Territories, Canada (75.5° N, 96.1° W: paleocoordinates 2.1° N, 39.5° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Thumb Mountain Formation (Cornwallis Group), Chatfieldian to Chatfieldian (460.9 - 449.5 Ma)

• from upper 50 feet of formation; lower than zone B

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified lime mudstone

Size class: macrofossils

Collected by R. Thorsteinsson in 1950-53; reposited in the GSC

Collection methods: surface (in situ),

Primary reference: R. Thorsteinsson. 1958. Cornwallis and Little Cornwallis Islands, District of Franklin, Northwest Territories. Geological Survey of Canada Memoirs 294:1-134 [M. Hopkins/M. Hopkins/M. Hopkins]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 188774: authorized by Melanie Hopkins, entered by Melanie Hopkins on 18.09.2017

Creative Commons license: CC BY (attribution)

Taxonomic list

• Identified with help from T. E. Bolton (bryozoans) and A. E. Wilson (remainder)
 Phacopida - Pterygometopidae
"Calliops cf. narrawayi" = Calyptaulax
"Calliops cf. narrawayi" = Calyptaulax trilobite
 Strophomenida - Sowerbyellidae
Sowerbyella sp. Jones 1928
 Pentamerida - Parastrophinidae
"Parastrophinella cf. hemiplicata" = Parastrophina hemiplicata
"Parastrophinella cf. hemiplicata" = Parastrophina hemiplicata Hall 1847
subspecies minor
 Atrypida - Cyclospiridae
? Cyclospira sp. Hall and Clarke 1893
 Orthida - Dalmanellidae
 Orthida - Hesperorthidae
? Hesperorthis sp. Schuchert and Cooper 1931
 Orthida - Plectorthidae
Plectorthis sp. Hall and Clarke 1892
 Cryptostomida -
Rhinidictya sp. Ulrich 1882