Derived from the characteristically coloured marls and sandstones which occur beneath the chalk is a late Cretaceous lithostratigraphic group,  particularly along the coast of one of six countries that make up what?
Hibernian Greensands Group The Hibernian Greensands Group is a late Cretaceous lithostratigraphic group (a sequence of rock strata) in Northern Ireland. The name is derived from the characteristically coloured marls and sandstones which occur beneath the chalk particularly along the Antrim coast. The strata are exposed on or near to both the northern and eastern coasts of Antrim and also between Portrush and Dungiven within County Londonderry. Further outcrops occur between Belfast and Lurgan and between Dungannon and Magherafelt. 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. Various units were earlier referred to as glauconitic or chloritic marls. This group and the overlying Ulster White Limestone Group are the stratigraphical equivalent of the Chalk Group of southern and eastern England.
Skrinkle Sandstones Group The Skrinkle Sandstones Group is a late Devonian to early Carboniferous lithostratigraphic group (a sequence of rock strata) in west Wales. The name is derived from the bay of Skrinkle Haven in south Pembrokeshire. The Group comprises the Gupton and overlying West Angle formations and is up to 300m thick. It was deposited south of the east-west aligned Ritec Fault.