The Lateral Key for the Identification of the Commoner Lower Carboniferous Coral Genera was first published in The North West Geologist No. 2, in the spring of 1992. Carboniferous Limestone rocks (usually coloured pale blue on geological maps) occur widely in Britain and form attractive and varied scenery. Many of the outcrops are in National Parks or areas of outstanding beauty. The limestones were mainly formed by the remains of a rich variety of ancient life, in relatively shallow, warm tropical seas. Two groups of fossils are common, brachiopod shells and corals, identification of the latter being the subject of this key.