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.
Geology of Algeria The geology of Algeria is diverse; the country divides into three different tectono-stratigraphic domains. In the south and west is the West African Craton which consists of Precambrian granitic basement and surrounding Neoproterozoic mobile belts. Further south the Tuareg Shield comprises the Hoggar, Adrar des Iforas and Air sub-shields which have each been affected by tectono-thermal events touching much of the continent. In the north are the Alpine chain mountains with a succession of folded and over-thrusted strata.