This intrusion of peralkaline syenite and granite forms a ridge 3.5 km in length and is intruded into Precambrian metavolcanics, schists and granodiorites. Volcanic rocks, including trachytic agglomerates and tuffs, latites and rhyolites are preserved as infaulted wedges and as roof remnants to the syenite. Dykes of solvsbergite and bostonite are numerous in the country rocks and include radial and curving dykes, the latter being interpreted as ring-dykes. Rock analyses will be found in El Ramly et al. (1971) and El Reedy and El Sokkary (1982).