Île St-Jean, Montreal ("Terrebonne Fm.") (Ordovician to of Canada)

Also known as Isle St. Jean, St. John Island, Hochelaga Archipelago, St. Lawrence Lowland

Where: Quebec, Canada (45.7° N, 73.6° W: paleocoordinates 25.9° S, 50.7° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Terrebonne Member (Tetreauville Formation), Shermanian to Shermanian (457.3 - 450.2 Ma)

• "Terrebonne formation" Flower (1952). When Flower wrote the paper used as reference here, the Terrebonne was considered a seperate formation. Today it is regarded as a facies variation of the Tetreauville Fm. (see Harland & Pickerill, 1982, Geol. Mag. 17; see also comments on lithology). Nevertheless it is given here as a member of the Tetreauville in order to include the name in the collection record. The Tetreau(lt)ville Fm. is Shermanian to Edenian in age according to Melchin & Legault (1985, Palynology 9).

• group of beds-level stratigraphic resolution

Environment/lithology: deep subtidal shelf; burrowed, nodular, rubbly, argillaceous limestone and shale

• "Sediments composing the Tetreauville Formation were deposited in an offshore, relatively deep subtidal environment where fine grained material accumulated slowly, mainly from suspension. [...] The more compact nodular limestones of the Terrebonne facies probably represent more thoroughly bioturbated parts of the sequence and perhaps relate to even lower rates of deposition." (Harland & Pickerill, 1982 p. 146).
• "The regular alternation of limestone and shale [of the Tetreauville Fm. sensu strictu] is occasionally replaced, usually in the higher parts of the formation but sometimes lower, by rubbly or nodular-bedded argillaceous limestones separated by indistinct thin shale layers and lenses. These parts of the sequence were originally thought sufficiently distinct to be termed the Terrebonne Formation (Clark 1952) but were later considered to be a 'floating' member of the Tetreauville Formation (Clark 1972) and are now known to be a simple facies variation (Clark and Globensky 1976a,b)." (Harland & Pickerill, 1982 p. 146).

Size class: macrofossils

Preservation: cast

Primary reference: R. H. Flower. 1952. New Ordovician Cephalopods from Eastern North America. Journal of Paleontology 26(1):24-59 [B. Kröger/T. Liebrecht]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 89110: authorized by Björn Kröger, entered by Torsten Liebrecht on 05.05.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Cephalopoda
 Oncocerida - Diestoceratidae
Diestoceras lavalense n. sp.
Diestoceras lavalense n. sp. Flower 1952
holotype: a specimen in the collections of G. Winston Sinclair
 Multiceratoidea - Apsidoceratidae
Apsidoceras quebecense
Apsidoceras quebecense Flower 1952
1 paratype in the collections of G. W. Sinclair, and 1 additional specimen, the repository of which is not mentioned (presumably Sinclair collection as well)