The Callovian is a stage on the
geologic time scaleoccurring 164.7 ± 4.0 Ma to 161.2 ± 4.0 Ma (million years ago).It is the last stage of the Middle Jurassic.
The stage takes its name from an old spelling of
Kellaways Bridge, 3 km north-east of Chippenham in Wiltshirein England.
During the Callovian,
Europewas an island chain.
Members of the order ammonitda are known as Ammonitic ammonites. They are distinguished primarily by their suture lines. In ammonitic suture patterns, the lobes and saddles are much subdivided (fluted) and subdivisions are usually rounded instead of saw-toothed. Ammonoids of this type are the most important species from a biostratigraphical point of view. This suture type is characteristic of
Jurassicand Cretaceousammonoids but extends back all the way to the Permian.
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Callovian — … Useful english dictionary
Callovian Stage — ▪ geochronology uppermost of the four divisions of the Middle Jurassic Series, representing all rocks formed worldwide during the Callovian Age, which occurred between 164.7 million and 161.2 million years ago during the Jurassic Period.… … Universalium
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