Bed 20, St. Joseph's Island [Swift Current Fm, = Gull River Fm] (Ordovician of Canada)

Where: Ontario, Canada (46.2° N, 83.9° W: paleocoordinates 21.5° S, 56.9° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Gull River Formation, Franklinian (460.9 - 449.5 Ma)

• STRATIGRAPHIC RELATIONS: From the Gull River Fm (referred to as Swift Current Fm), which locally overlies the Munising Fm (Cambrian) and is overlain by the Collingwood Fm (Late Ordovician). AGE: Middle Mohawkian or Early Franklinian; Caradocian; on the basis of conodont faunas. STRATIGRAPHIC POSITION: From bed 20 in section

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified limestone

• SPECIFIC LITHOLOGY: Limestone. LITHIFICATION: Lithified, on the basis of lithology and sample preparation.

Size class: macrofossils

Collected by Darby

Collection methods: bulk, chemical, sieve,

• COLLECTOR: D. G. Darby, unknown date. REPOSITORY: Not stated, but probably the Dept of Geology, University of Minnesota.

Primary reference: D. G. Darby. 1982. The early vertebrate Astraspis, habitat based on a lithologic association. Journal of Paleontology 56(5):1187-1196 [A. Hendy/A. Hendy]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 90411: authorized by Austin Hendy, entered by Austin Hendy on 19.07.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Limited to taxa discussed in text. NOMENCLATURE: Not an authoritative publication, but with modern nomenclature and species-resolution identifications.
Conodonta
 Conodonta -
Pteraspidomorpha
 Astrapidiformes - Astraspididae