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?
County Antrim County Antrim (named after the town of Antrim, from Irish: "Aontroim" , meaning "lone ridge" , )) is one of six counties that form Northern Ireland. Adjoined to the north-east shore of Lough Neagh, the county covers an area of 3046 km2 and has a population of about 618,000. County Antrim has a population density of 203 people per square kilometer / 526 people per square mile. It is also one of the thirty-two traditional counties of Ireland, as well as part of the historic province of Ulster.
Large igneous province In geology, a large igneous province (LIP) is an extremely large accumulation of igneous rocks, including plutonic rocks (intrusive) or volcanic rock formations (extrusive), arising when hot magma extrudes from inside the Earth and flows out. The source of many or all LIPs is variously attributed to mantle plumes or to processes associated with plate tectonics. Types of LIPs can include "large volcanic provinces" (LVP), created through flood basalt, and "large plutonic provinces" (LPP). Rampino and Stothers (1988) cite eleven distinct flood-basalt episodes - occurring in the past 250 million years - which created volcanic provinces and plateaus and coincided with mass extinctions. However, more flood basalts have been recognized, such as the large Ontong Java Plateau, and the medium-sized Chilcotin Group, though the latter may be linked to the Columbia River Basalt Group. Formation depends on a range of factors, such as continental configuration, latitude, volume, rate, duration of eruption, style and setting (continental vs. oceanic), the pre-existing climate state, and the biota resilience to change.