This is a faulted intrusion, lens-shaped in plan having a width of 100-800 m and an area of 2.5 km2. It is composed of banded clinopyroxenites rich in apatite and biotite and sometimes containing melanite and K-feldspar. A subordinate role is played by melanocratic and leucocratic mica shonkinites which sometimes contain pseudoleucite and altered olivine. The massif is cut by thin dykes of alkaline syenite and ledmorite, which are intensively granitised and altered to mica along the contacts. The intrusion has been intensively mylonitised and autometasomatically altered.