Catoche Formation type section (Ordovician of Canada)

Where: Newfoundland and Labrador, Canada (50.7° N, 57.4° W: paleocoordinates 30.6° S, 46.7° W)

• coordinate estimated from map

• local area-level geographic resolution

When: Strigigenalis caudata trilobite zone, Catoche Formation (St. George Group), Cassinian (482.3 - 470.0 Ma)

• Measured section is shown with dots indicating collection horizons but fossils occurrences are shown only as ranges rather than occurrences or only partially listed in plate captions.

• formation-level stratigraphic resolution

Environment/lithology: open shallow subtidal; bioturbated, nodular, rubbly limestone and dolomite

• "It is generally accepted that the St. George Group as a whole is a relatively shallow water carbonate succession...Few stromatolitic beds are present in the Catoche Formation, but in the lower part there are frequent intraformational conglomerate beds, sometimes with clasts stacked edgewise, and occasional oolitic lenses...The concentration of the trilobites into lime sand lenses, and their complete disarticulation, often with breakage of the more delicate cephalic parts, indicates the activity of currents and/or tides was at least powerful enough to break, move, and 'winnow' trilobite skeletal parts...The appearance of the pelagic trilobites Carolinites and Opipeuter in the section is significant because it indicates free connection with the open oceans..."
• "Thin bedded and rubbly surfaced limestone, with many styolite seams. Thin dolomite beds form recessive units less than half a meter thick at intervals through the section...Massive limestone increases toward the top of the section, and is progressively more dolomitized. Elsewhere dolomitization occurs preferentially along numerous bifurcating "worm" trails, producing a mottled appearance on fresh rock surfaces. Trilobites are most numerous in lenses of lime sand...The upper part of the Catoche Formation includes some apparently structureless mounds several meters in diameter."

Size class: macrofossils

Collected by R. A. Fortey in 1978; reposited in the GSC

Collection methods: mechanical,

• Collected from fairly regular intervals in section but notes that trilobites were most easily recovered from lenses of lime sand which were most abundant in middle of section. Only Bolbocephalus and Petigurus (asaphids) were recovered from main body of limestone.

Primary reference: R. A. Fortey. 1979. Early Ordovician trilobites from the Catoche Formation (St. George Group), western Newfoundland. Geological Survey of Canada Bulletin 321:61-114 [M. Hopkins/M. Hopkins]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 103540: authorized by Melanie Hopkins, entered by Melanie Hopkins on 29.01.2011

Creative Commons license: CC BY (attribution)

Taxonomic list

• Macluritid gastropods and nautiloids common; gastropods also concentrated in more massive limestones that cap small bluffs along the shore. Receptaculites, Calathium and ?Bryozoa found in sections made from main body of limestone.
 Phacopida - Pliomeridae
Strotactinus insularis Billings 1865 trilobite
 Asaphida - Asaphidae
"Isoteloides latimarginatus n. sp." = Isoteloides canalis, Isoteloides peri n. sp.
"Isoteloides latimarginatus n. sp." = Isoteloides canalis Whitfield 1886 trilobite
Isoteloides peri n. sp. Fortey 1979 trilobite
 Proetida - Telephinidae
Carolinites genacinaca Ross 1951 trilobite
subspecies nevadensis
Opipeuter cf. angularis Young 1973 trilobite
 Proetida - Bathyuridae
Bolbocephalus convexus Billings 1865 trilobite
Petigurus nero Billings 1865 trilobite
Catochia glabra n. sp. Fortey 1979 trilobite
Catochia ornata n. gen. n. sp. Fortey 1979 trilobite
"Jeffersonia jenni" = Jeffersonia jenni2 Cullison 1944 trilobite
"Jeffersonia angustimarginata" = Jeffersonia jenni1 Cullison 1944 trilobite
pygidium originally assigned to Bathyurina timon
"Bathyurina timon" = Jeffersonia timon Billings 1865 trilobite
Benthamaspis gibberula Billings 1865 trilobite
Benthamaspis conica n. sp. Fortey 1979 trilobite
Uromystrum cf. affine Poulsen 1937 trilobite
Punka sp. Fortey 1979 trilobite
Punka flabelliformis n. sp. Fortey 1979 trilobite
Bathyurellus abruptus Billings 1865 trilobite
Bathyurellus platypus n. sp. Fortey 1979 trilobite
Strigigenalis caudata Billings 1865 trilobite
 Proetida - Dimeropygidae
Ischyrotoma anataphra n. sp. Fortey 1979 trilobite