The coastal dyke swarm and associated flexure, plutonic intrusions and volcanics are the products of a short episode of rifting between normal and thinned continental crust during initial opening of the Atlantic Ocean between Greenland and the Rockall Plateau 56–52 m.y. ago. They constitute a continental rift zone which provides deeply eroded onshore examples of phenomena which probably lie buried beneath the sea along major rifted continental margins. The dyke swarm occurs in a series of zones arranged en echelon, similar to dyke and fissure swarms in Iceland. Most dykes were intruded vertically before flexuring rather than as a fan during flexuring as postulated by Wager and Deer [1]. Layered gabbro plutons and basic cone sheets were emplaced during early stages of flexuring. Magma was tapped westwards along the upper limb of the developing flexure to form the Skaergaard and Kap Edvard Holm intrusions, but intrusions such as Imilik and Kap Gustav Holm in the steep limb show more complex histories of synplutonic tilting, slumping and deformation. Most flexuring occurred after consolidation of the gabbros and was followed by the intrusion of linear and radial swarms of intermediate dykes and ring dykes associated with the emplacement of syenite and granite plutons by cauldron subsidence.