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.
Coastline of the United Kingdom The coastline of the United Kingdom is formed by a variety of natural features including islands, bays, headlands and peninsulas. It consists of the coastline of the island of Great Britain and the north-east coast of the island of Ireland, as well as a large number of much smaller islands. Much of the coastline is accessible and quite varied in geography and habitats. Large stretches have been designated areas of natural beauty, notably the Jurassic Coast and the Heritage Coast.