AND

ABSTRACT. The Cadomian igneous complex of N. Guernsey includes gabbro, diorite, granodiorite, and adamellite. The gabbro is layered, shows variations in colour index and texture, contains abundant amphibole, and is cut by the diofites. The diorites how little variation in mineral compositions despite considerable variation in modal proportions. They contain numerous thin and roughly parallel veins of leucodiorite and granodiorite, and layers of meladiorite occur in several places within the veined diorites. These meladiorites, previously interpreted as separate intrusions, form individual layers from a few centimetres toseveral metres thick which can be traced for some tens of metres along strike. The upper surfaces of the meladiorites are planar but the lower tend to be indented and irregular. The layers thin out laterall