The glacial and fluvioglacial deposits preserved in the Middle Maruia Valley record the advances and retreats of the Maruia glacier during and since the Otira Glaciation. From the spatial distribution of the various moraines and outwash surfaces five major Otiran advances, and one minor Postglacial advance, are recognised. These are, from oldest to youngest, the Creighton I, II, III Advances, the Reid Stream I, II Advances, and the Springs Advance. There was an interstadial interval between the Creighton III and Reid Stream I advances. A radiocarbon date obtained by Suggate (1965) would suggest that the climax of the Reid Stream I Advance occurred shortly after 14,800 yrs B.P. Prior to several of the advances lakes became impounded in the valley. The largest of these, Lake Maruia, extended more than 15 km upvalley from the Creighton I moraine loop. It existed during the Creighton-Reid Stream Interstadial. The Maruia Otira Glacial Chronology can be correlated reasonably well with the Waiau and Waimakariri glacial sequences. However, a good correlation cannot be made with the standard N.Z. sequence, thus a revised New Zealand Otiran Glacial Chronology is proposed.