• Source: 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.




Description


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.




Fossil content


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. Also ostracods, trilobites, bivalves, gastropods, cephalopods and other fossils were found in the formation.




See also


List of fossiliferous stratigraphic units in Ontario
Arnheim Formation, contemporaneous fossiliferous formation of Ohio
San Benito Formation, contemporaneous fossiliferous formation of Bolivia
Late Ordovician glaciation
Ordovician meteor event
Taconic orogeny




References






= Bibliography

=
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

Kata Kunci Pencarian:

• Verulam Formation
• Endoceras
• Isotelus
• Reteocrinus
• Ceraurinus
• Actinoceras
• Plaesiomys
• Ceraurus
• Rafinesquina
• Iocrinus