A new formation—Colville Formation—is proposed for newly discovered outcrops of Tertiary sedimentary rocks near Cape Colville, Coromandel Peninsula. Along with a small area previously mapped as Torehina Formation (Te Kuiti Group), the rocks are correlated with Waitemata Group of the Auckland region on the basis of fauna, lithologies, and conformity with overlying andesitic deposits of Beesons Island Volcanics. The correlation provides a link between the andesitic eruptions of West Auckland and the early volcanism of the Coromandel Peninsula.