Synopsis: Sixty-five holes drilled between Huntly and Portsoy have shown that undeformed, basic igneous rocks in this region occupy a smaller area than is shown on existing maps and that the single intrusion previously recognised—the ‘Huntly mass’—does not exist. Three smaller bodies of basic rock, which appear to consist largely of cumulates and xenolithic rocks, can be identified. The structures in the cumulates appear to be nearly vertical in most instances, but no clear evidence of folding has been found in these rocks, although certain of the igneous boundaries appear to have been intensely deformed. Xenoliths are highly metamorphosed, but otherwise there is little evidence of thermal metamorphism in the vicinity of the basic rocks, even when the latter consist of cumulates.