This complex is only marginally alkaline. It consists of two intrusions of approximately 3.5x0.6 km elongated east-west and separated by a narrow zone of Burundian-Kibaran mica schists. The northern intrusion is of microsyenite: the southern of microgranite. Both rock types comprise perthite, albite and a little biotite; the principal mafic mineral of the granite is ferropargasitic hornblende, but of the syenite hedenbergite and fayalite; there is a little fluorite in the syenite. Pyroxene, amphibole and ilmenite analyses are given by Rumvegeri et al. (1985) and one of the analyses of amphibole microgranite contains acmite in the norm.