The Ravenscar Group is a

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

lithostratigraphic Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneous ...

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

(a sequence of

rock strata In geology and related fields, a stratum (: strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ...

) found within the

Cleveland Basin The Cleveland Basin is a sedimentary basin in Yorkshire, England. Formed initially by rifting during the Mississippian period of the Early Carboniferous. It is West–East trending and lies between the intrabasinal highs of the Askrigg Block a ...

North Yorkshire North Yorkshire is a Ceremonial counties of England, ceremonial county in Northern England.The Unitary authorities of England, unitary authority areas of City of York, York and North Yorkshire (district), North Yorkshire are in Yorkshire and t ...

, extending into both the Hambleton and

Howardian Hills The Howardian Hills are a range of hills in England located between the Yorkshire Wolds, the North York Moors, and the Vale of York. They are named after the Howard family, who still own land locally, and have been designated a National Land ...

. The name is derived from Ravenscar on the

coast, where rocks of this age occur. It was previously known as the 'Middle Jurassic Series'.British Geological Survey 1:50,000 scale geological map sheet (England and Wales series) no 34 ''Guisborough'' It is stratigraphic equivalent to the

Inferior Oolite Group The Inferior Oolite is a sequence of Jurassic age sedimentary rocks in Europe. It was deposited during the Middle Jurassic.Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, Europe)." In: Weishampel, David B.; Dodson, Pet ...

and most of the

Great Oolite Group The Great Oolite Group is a Middle Jurassic stratigraphic unit that outcrops in southern England. It consists of a complex set of marine deposits primarily mudstone and bioclastic ooidal and fine grained limestone, deposited in nearshore to ...

, being overlain by the Cornbrash Formation of the latter unit.

References

Geological groups of the United Kingdom Geologic formations of England Aalenian Stage Bajocian Stage Bathonian Stage Geology of North Yorkshire {{UK-geologic-formation-stub