The Ulster White Limestone Group is a late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

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

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 ide ...

(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 ei ...

) in

Northern Ireland Northern Ireland ( ga, Tuaisceart Éireann ; sco, label= Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. Nort ...

. The name is derived from the characteristic chalk rock which occurs particularly along the Antrim coast. The

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 ei ...

are exposed on or near to both the northern and eastern coasts of Antrim and also between

Portrush Portrush () is a small seaside resort town on the north coast of County Antrim, Northern Ireland. It neighbours the resort of Portstewart. The main part of the old town, including the Portrush railway station, railway station as well as most hote ...

and

Dungiven Dungiven () is a small town, townland and civil parish in County Londonderry, Northern Ireland. It is near the main A6 Belfast to Derry road, which bypasses the town. It lies where the rivers Roe, Owenreagh and Owenbeg meet at the foot of the B ...

within

County Londonderry County Londonderry ( Ulster-Scots: ''Coontie Lunnonderrie''), also known as County Derry ( ga, Contae Dhoire), is one of the six counties of Northern Ireland, one of the thirty two counties of Ireland and one of the nine counties of Ulster. B ...

. Further outcrops occur between

Belfast Belfast ( , ; from ga, Béal Feirste , meaning 'mouth of the sand-bank ford') is the capital and largest city of Northern Ireland, standing on the banks of the River Lagan on the east coast. It is the 12th-largest city in the United Kingdo ...

and

Lurgan Lurgan () is a town in County Armagh, Northern Ireland, near the southern shore of Lough Neagh. Lurgan is about south-west of Belfast and is linked to the city by both the M1 motorway and the Belfast–Dublin railway line. It had a population ...

and between

Dungannon Dungannon () is a town in County Tyrone, Northern Ireland. It is the second-largest town in the county (after Omagh) and had a population of 14,340 at the 2011 Census. The Dungannon and South Tyrone Borough Council had its headquarters in the ...

and

Magherafelt Magherafelt (, �mˠaxəɾʲəˈfʲiːlt̪ˠə is a small town and civil parish in County Londonderry, Northern Ireland. It had a population of 8,805 at the 2011 Census. It is the biggest town in the south of the county and is the social, econo ...

. The current names replace an earlier situation where the present group was considered to be a formation and each of the present formations was considered a 'member'. Several other stratigraphic naming schemes were in use during the nineteenth century and much of the twentieth century.Hopson, P.M., 2005 ''A Stratigraphical Framework for the Upper Cretaceous Chalk of England and Scotland with Statements on the Chalk of Northern Ireland and the UK Offshore Sector'', British Geological Survey Research Report RR/05/01 (downloaded from www.bgs.ac.uk) This group and the underlying Hibernian Greensands Group are the stratigraphical equivalent of the

Chalk Group The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur acr ...

of southern and eastern England.

Stratigraphy

* Post-Larry Bane Chalk Subgroup ** Ballycastle Chalk Formation ** Port Calliagh Chalk Formation ** Tanderagee Chalk Formation ** Ballymagarry Chalk Formation ** Portush Chalk Formation ** Garron Chalk Formation ** Glenarm Chalk Formation ** Ballintoy Chalk Formation * Larry Bane Chalk Formation * Pre-Larry Bane Chalk Subgroup ** Boheeshane Chalk Formation ** Greggan Chalk Formation ** Cloghastucan Chalk Formation ** Galboly Chalk Formation ** Clogfin Sponge Formation There is an

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

(non-sequence) at the base of the Boheeshane Chalk Formation.

References

Geologic groups of Europe Geologic formations of Ireland Geology of Northern Ireland Upper Cretaceous Series of Europe Limestone formations {{UK-geologic-formation-stub