Becscie Formation

Geologic formation in Quebec, Canada From Wikipedia, the free encyclopedia

The Becscie Formation is a geologic formation in Quebec. It preserves fossils dating back to the early Silurian period.

TypeGeological formation
Sub-units
  • Fox Point Member (lower)
  • Chabot Member (upper)
UnderliesGun River Formation
OverliesEllis Bay Formation
Quick facts Type, Sub-units ...
Becscie Formation
Stratigraphic range: Early Silurian
TypeGeological formation
Sub-units
  • Fox Point Member (lower)
  • Chabot Member (upper)
UnderliesGun River Formation
OverliesEllis Bay Formation
Thickness80 to 85 meters
Location
RegionQuebec
CountryCanada
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Description

The Becscie Formation is 80 to 85 meters thick.[1] It overlies the Ordovician-Silurian boundary on Anticosti Island, marking a major oceanic and climatic changeover from the glacial sea-level lowstand and interglacial highstand cycles of the underlying Ellis Bay Formation to the more stable warming climate of the earliest Silurian, and extends approximately parallel to an ancient coastline some 200 km east to west.[1] The formation is divided into two members, a lower Fox Point Member (spanning the Viridita lenticularis Biozone), and an upper Chabot Member (spanning the Virgiana barrandei Biozone).[1]

Fossil content

More information Arthropods, Genus ...
Arthropods
GenusSpeciesPresence MaterialNotesImages
Anticostibolbina Chabot Member.[1] A beyrichiacean ostracod.
Bolbineossia Chabot Member.[1] A beyrichiacean ostracod.
Conbathella Chabot Member.[1] A beyrichiacean ostracod.
Herrmannina H. selwyni Lower Becscie Formation.[1] An ostracod
Zygobursa Chabot Member.[1] A beyrichiacean ostracod.
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More information Brachiopods, Genus ...
Brachiopods
GenusSpeciesPresence MaterialNotesImages
Becscia B. scissura "Occurs commonly in lenses and clusters".[1] An atrypid.[1]
Biparetis Elsewhere known from the early Silurian, but locally rare.[1]
Brachyprion Occurs sparsely in the Chabot Member.[1]
Eospirigerina E. sp. Fox Point Member.[1] An unnamed species, represents earliest known Silurian species of this Ordovician genus.
Hesperorthis Fox Point Member.[1] An orthide.[1]
Isorthis (Ovalella) Fox Point Member.[1] An orthide.[1]
Koigia An athyridid, originally reported as Hindella.[1]
Leptaena Fox Point Member bedding plane.[1]
Mendacella M. udauberis Fox Point Member, rare in the Chabot Member.[1] An orthide.[1]
Saukrodictya Fox Point Member.[1] An orthide.[1]
Virgiana V. barrandei Only in the Chabot Member.[1][2] A large-shelled pentameride.[1]
Viridita V. becsciensis Fox Point Member.[2] "Holotype, YPM 10341, and paratype, YPM 35519".[2]
V. lenticularis Near the top of the Fox Point Member,[1] and the Chabot Member.[2]
Zygospiraella Z. cf. Z. planoconvexa Lower Becscie Formation, rare taxon in the lower Chabot Member.[1]
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More information Bryozoans, Genus ...
Bryozoans
GenusSpeciesPresence MaterialNotesImages
Phaenopora P. superba Fox Point and Chabot Members.[1] "Extends into the overlying Gun River Formation"[3]
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More information Corals, Genus ...
Corals
GenusSpeciesPresence MaterialNotesImages
Acidolites A. arctatus [4] A heliolitid.
A. compactus [4] A heliolitid.
A. lindströmi [4] A heliolitid.
Nanonphyllum N. pelagicum Common in the Chabot Member.[1] A colonial rugose coral.
Paleofavosites More common towards the upper part of the Fox Point Member.[1] A heliolitid tabulate coral.[1]
Palaeophyllum Common in the Chabot Member.[1]
Propora More common towards the upper part of the Fox Point Member.[1] A heliolitid tabulate coral.[1]
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More information Crinoids, Genus ...
Crinoids
GenusSpeciesPresence MaterialNotesImages
Alopocrinus Fox Point and Chabot members.[1]
Becsciecrinus Fox Point and Chabot members.[1]
Dendrocrinus Chabot Member.[1]
Eumyelodactylus Fox Point Member.[1]
Euspirocrinus Fox Point Member.[1]
Protaxocrinus Fox Point Member.[1]
Xenocrinus Chabot Member.[1]
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More information Gastropods, Genus ...
Gastropods
GenusSpeciesPresence MaterialNotesImages
Hormotoma Eastern side of Anticosti Island.[1] A hormotomid.
Subulites Eastern side of Anticosti Island.[1] A soleniscid.
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More information Graptolites, Genus ...
Graptolites
GenusSpeciesPresence MaterialNotesImages
Climacograptus C. typicalis var. atlanticus [5]
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More information Sponges, Genus ...
Sponges
GenusSpeciesPresence MaterialNotesImages
Clathrodictyon C. boreale Fox Point and Chabot members.[1] "A single small, spheroidal specimen".[1] A stromatoporoid.[1]
Ecclimadictyon E. macrotuberculatum Chabot Member.[1] A stromatoporoid.
Pachystylostroma Very top of the Chabot Member.[1] A stromatoporoid.
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See also

References

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