larger olivine crystals accumulated above the chilled base, a few of the smaller were retained by the stiffening melt near the upper margin. 2. “Although the sinking of the two minerals probably overlapped, crystalisation of olivine ceased at an early stage, when the magma was still fluid, whereas pyroxene continued to form and to sink until brought to rest by the increasing viscosity of the magma and by crystal interference.” 3. “There was no appreciable sinking of iron ore.” 4. “Interstitial alkaline feldspars are found in the upper portion of the sheet with micropegmatite and free quartz in its higher parts,” but there is no evidence of albitisation or formation of albitic veinlets such as occur in the Palisade Sill. 5. The later stages of crystallisation were followed by pronounced hydrothermal activity resulting in formation of chlorophaeite and chloritic minerals with chalcedony chiefly at the expense of residual glass, bowlingite, quartz, chalcedony, and ferruginous and calcic carbonates, more or less in the above order. 6. Though the thickness of this sheet is so much less than that of the Palisade Sill or the Tasmanian sills (above 1000 feet) the range of average grain size of the plagioclase is but little different from that throughout the Palisade Sill and the lower 700 ft of the Tasmanian Mt. Wellington Sill. Probably this resulted from a greater content of water in the magma, which also facilitated the gravitational differentiation. 8. Olivine dolerite (5874) near the base, and quartz dolerite (5869) 200 feet above the base of the Main Moeraki Sheet. (e) The Main Moeraki Dolerite Sheet. The obscuring drift on hill-slopes prevents a detailed tracing of the differentiation-sequence in this sheet, though it may later be accomplished by a study of the high cliff half a mile north-west of the lighthouse the base of which consists of olivine dolerite and the top of quartz dolerite. (See Benson, 1943, Fig. 8.) The two end-members of the series are however, widespread. Olivine dolerite occurs always near the base of the intrusive sheet as at Tawitiatiauka (5860) and a quarter of a mile west thereof (5790) by the shore