The Cobourg Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

. It preserves

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

dating back to the

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

. Technically the formation extends into

New York State New York, also called New York State, is a state in the northeastern United States. Bordered by New England to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and ...

with Canadian section called

Lindsay Formation The Lindsay Formation is a geologic formation in Ontario. It preserves fossils dating back to the Ordovician period. See also * List of fossiliferous stratigraphic units in Ontario This is a list of stratigraphic units in Ontario bearing foss ...

. The formation was named by Raymond (1921). The Cobourg formation was estimated to have a total thickness of about 70 m.

Fossil found in the Cobourg Formation

* An example of a trilobite that lived during the Upper

Flexicalymene ''Flexicalymene'' is a genus of trilobites belonging to the order Phacopida, suborder Calymenina and family Calymenidae. ''Flexicalymene'' specimens can be mistaken for ''Calymene'', '' Gravicalymene'', '' Diacalymene'' and a few other Calymenin ...

croneisi. Found in 1941, in the Cobourg formation.

References

* * Various information of the Cobourg Formation and Colborne quarry
"FABRIC OF A MIDDLE ORDOVICIAN LIMESTONE AT COLBORNE, ONTARIO"
Retrieved 9 February 2024.
"Ordovician Trilobites of Canada (alphabetized)"
Retrieved 9 February 2024. Ordovician Ontario Ordovician geology of New York (state) Ordovician southern paleotemperate deposits Geologic formations of Ontario Limestone formations of Canada {{Ontario-geo-stub