This review of the chiefly magmatic Tertiary rocks in the central parts of East and West Greenland shows that the most abundant magmas were tholeiitic, and the most primitive magmas probably formed the picrites of Wesl Greenland. The voluminous quartz tholelites are very similar in composition to those of other plateau-basalt areas. Present in smaller amounts are alkalic basalt and nephelinitic types. The predominant salic magma was a nordmarkile, which differentiated to foyaite and peralkalic granite. Stratigraphic and radiometric evidence shows that magmatic activity was limited to the Paleocene and Eocene, and indicates that the lava was extruded at roughly the same rate as were postglacial Icelandic lavas. Tectonism was characterized by uplift of continental blocks an subsidence of adjoining areas. The abundant tholeliitic volcanism was associated with early rifting in the Paleocene, whereas the production of alkalic rock types probably occurred after the area had migrated away from the most active zone.