Early Miocene fossiliferous andesitic sediments are associated with some ophiolite massifs in northern Northland: Otaian volcanic grits (Hughes 1966) form a part of Maungaru Range (Fig. 3) and Waitakian–Otaian volcaniclastics are intruded by microdiorite near North Cape (Leitch 1966, 1970).
Source: wiktionary