Wikipedia

Verulam Formation

The Verulam Formation is a geologic formation and Lagerstätte in Ontario, Canada. It preserves fossils dating back to the Katian stage of the Ordovician period, or Shermanian to Chatfieldian in the regional stratigraphy.[1]

Verulam Formation
Stratigraphic range: Sandbian to Katian
Outcrop along Kirkfield Rd., Kawartha Lakes.
TypeFormation
Unit ofSimcoe Group
Trenton Group
Sub-unitsCystid Beds
UnderliesLindsay Formation
Cobourg Formation
OverliesBobcaygeon Formation
Kirkfield Formation
Lithology
PrimaryLimestone
OtherMudstone, shale, siltstone
Location
Coordinates44°36′N 79°06′W / 44.6°N 79.1°W / 44.6; -79.1
Approximate paleocoordinates23°54′S 52°06′W / 23.9°S 52.1°W / -23.9; -52.1
RegionOntario
Country Canada
Type section
Named byB.A Liberty
Year defined1955
Verulam Formation is located in Canada
Verulam Formation
Verulam Formation
Verulam Formation (Canada)
Verulam Formation is located in Ontario
Verulam Formation
Verulam Formation
Verulam Formation (Ontario)

Description

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The Verulam Formation belongs to the Simcoe Group in South-central Ontario and to the Trenton Group in Southwestern Ontario. Within the Simcoe Group, it overlies the Bobcaygeon Formation. Both the Bobcaygeon and Verulam Formations are composed of bioclastic wackestones, grainstones, and packstones interbedded with calcareous shales and siltstones. The Verulam contains more shale than the underlying Bobcaygeon Formation. Several hardgrounds have been documented in detail from the upper Bobcaygeon and lower Verulam. The paleoenvironments in which the Bobcaygeon and Verulam Formations were deposited have been interpreted as a proximal carbonate shelf that ranged in depth and proximity from shoal to shallow shelf in the Bobcaygeon and from deep shelf to shoal or shallow shelf in the Verulam Formation.[2]

Fossil content

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The Verulam Formation and the underlying Bobcaygeon Formation have provided many fossils. Both formations form the Brechin Lagerstätte, a Lagerstätte of excellent preservation of numerous exceptionally preserved crinoid specimens with arms, stems, and attachment structures intact.[2][3][4] Also ostracods, trilobites, bivalves, gastropods, cephalopods and other fossils were found in the formation.[5]

Crinoids
Trilobites
Edrioasteroidea
Ostracods
Strophomenata
Rhynchonellata
Bivalves
Gastropods
Cephalopods
Stenolaemata
Scyphozoa
Rhombifera
Chlorophyceae

See also

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References

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  1. ^ Verulam Formation
  2. ^ a b Carden Quarry at Fossilworks.org
  3. ^ a b Wright et al., 2019
  4. ^ Cole et al., 2018
  5. ^ Waddington, 1980
  6. ^ a b c d e f g Cole et al., 2020
  7. ^ Sumrall & Gahn, 2006
  8. ^ Sproat & Jin, 2013

Bibliography

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  • Cole, Selina R.; Wright, D.F.; Ausich, W. I.; Koniecki, J. M. (2020), "Paleocommunity composition, relative abundance, and new camerate crinoids from the Brechin Lagerstätte (Upper Ordovician)", Journal of Paleontology, 94 (6): 1103–1123, Bibcode:2020JPal...94.1103C, doi:10.1017/jpa.2020.32
  • Wright, D.F.; Cole, S.R.; Ausich, W.I. (2019), "Biodiversity, systematics, and new taxa of cladid crinoids from the Ordovician Brechin Lagerstätte", Journal of Paleontology, x (2): 1, Bibcode:2020JPal...94..334W, doi:10.1017/jpa.2019.81
  • Cole, S.R.; Ausich, W.I.; Wright, D.F.; Koniecki, J.M. (2018), "An echinoderm Lagerstätte from the Upper Ordovician (Katian), Ontario: taxonomic re-evaluation and description of new dicyclic camerate crinoids", Journal of Paleontology, x (3): 1–18, Bibcode:2018JPal...92..488C, doi:10.1017/jpa.2017.151
  • Sproat, C.D.; Jin, J. (2013), "Evolution of the Late Ordovician plaesiomyid brachiopod lineage in Laurentia", Canadian Journal of Earth Sciences, 50 (8): 872–894, Bibcode:2013CaJES..50..872S, doi:10.1139/cjes-2013-0022
  • Sumrall, C.D.; Gahn, F.J. (2006), "Morphological and systematic reinterpretation of two enigmatic edrioasteroids (Echinodermata) from Canada", Canadian Journal of Earth Sciences, 43 (4): 497–507, Bibcode:2006CaJES..43..497S, doi:10.1139/e05-114
  • Peters, S.E (2003), Evenness, richness and the Cambrian-Paleozoic faunal transition in North America: an assemblage-level perspective, University of Chicago, pp. 1–279
  • Waddington, J.B (1980), "A soft substrate community with edrioasteroids, from the Verulam Formations (Middle Ordovician) at Gamebridge, Ontario", Canadian Journal of Earth Sciences, 17 (5): 674–679, Bibcode:1980CaJES..17..674W, doi:10.1139/e80-064
  • Liberty, B.A (1969), "Palaeozoic geology of the Lake Simcoe Area, Ontario", Geological Survey of Canada Memoirs, 355: 1–201
  • Wilson, A.E (1951), "Gastropoda and Conularida of the Ottawa Formation of the Ottawa - St. Lawrence Lowland", Geological Survey of Canada Bulletin, 17: 1–149
  • Wilson, A.E (1946), "Echinodermata of the Ottawa Formation of the Ottawa-St. Lawrence lowland", Geological Survey of Canada Bulletin, 4: 1–61
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