This complex comprises a series of intrusions and associated volcanics forming a northwest-southeast-trending line over some 10 km. There are four distinct intrusions of peridotite with dunitic cores. These pass outwards into wehrlites, which in places then grade into olivine pyroxenites and clinopyroxenites. On the west of these bodies is an irregular intrusion of syenite bounded on its western margin by Devonian sandstones of the Furnas Formation. The syenite is nepheline-bearing and includes malignites and syenogabbros. There is also a little olivine gabbro. Areas of volcanic rocks were reported, but R. A. Fuck (personal communication to C. B. Gomes) says there are no volcanics, only dykes; these comprise phonolites, trachytes, tephrites, limburgites and nephelinites. Some fenitization occurs at the margin of the main intrusions.