The structure of the Sealy Range is obviously continued into that of the lower wall of the main divide between Scissors and Sefton, but its connection with the Mount Cook Range remains puzzling. The strikes of strata on both walls of the Mueller Glacier are very flexuous but make a consistent picture that can be related to the western dip slopes of an anticline whose crest, trending north, forms the ridge from Mt. Ollivier to Waihi Pass and beyond. On the east flanks of this anticline and immediately adjoining the crest the strata steepen rapidly to become vertical, and they are slightly overturned below the Mueller hut. Running along the east face of the Sealy ridge a shear zone separates this anticline from the lower slopes. The sequence at the shear zone is: Massive siliceous sandstone with thin layers of phyllite and quartz veins. Purple sheared rocks with green streaks. Hard green rock in lenses 1ft to 2ft thick. Purple shales. Sheared hard siliceous sandstone. Sub-schists with lineation down dip. Extending as far east as Sealy Tarn, these rocks are more metamorphosed than the rocks west of the shear zone and those below the lake. These beds dip west or west-south-west at some 60°. The purple and green rocks, 60ft to 100ft thick, are highly altered and sheared volcanics containing phenocrysts of albite, and appear to be albite-chlorite-epidote schists (A 63, 65). It is not clear whether they represent an original flow or a sill. The strike of the rocks between the Mueller Hut and Sealy Tarn is between 330° and 360°, but farther south the trend of shear zone is generally meridional. The zone has been traced as far as the upper part of Black Birch Creek, where the green and purple rocks, dipping very steeply west, must be over 300ft thick. From Sebastopol it can be seen that the north-westward dipping strata on the east wall of Sealy are upturned sharply, and the eastern limb of the Ollivier anticline is not visible. Presumably the shear zone continues beyond Sealy; east of its likely position, and south of the Hoophorn stream, from west to east, a broad well-defined overturned syncline, a sharp anticline and another less clearly-defined syncline occur, all with limbs dipping west. These folds can be expected to project northward, but their arches have not there been distinguished. The Ollivier anticlinal axis is also likely to be prolonged into the wall of Footstool, judging by the pattern of strikes along the Mueller Glacier. South of Sebastopol the approximate meridional strike of beds stand out regularly and clearly over a long distance. A marked scarp on the east face of Sebastopol must be controlled by a fault, for it coincides with a line along which the strike changes abruptly. East of the line, strikes oriented west and roughly north-west are probably related to those on the north-west side of Wakefield. Traces of indeterminable fossils have been observed in blue-black argillite (A 60) beside the water-pipe on the north bank of Sawyer Stream near the Unwin Hut. Region West of Main Divide (See Photo 7 for a view of localities.) Fox Glacier from Marcel Col to Chancellor Ridge On the walls of the Fox Glacier enough detail has been collected to present a general picture of structure, which can best best be described in terms of a traverse and views of neighbouring ridges along a route from Marcel Col on the Main Divide to the end of the glacier.