I have examined the specimens microscopically.
From Mount Betty there are several specimens of white granite, with dark and light mica; it has a great resemblance to the white granites from Sogn, the Dovre district, and Nordland, in Norway. There is one very beautiful specimen of shining white, fine-grained granite aplite, with small, pale red garnets. These granites show in their exterior no sign of pressure structure. The remaining rocks from Mount Betty are gneissic granite, partly very rich in dark mica, and gneiss (granitic schist); besides mica schist, with veins of quartz.
From Scott's Nunatak there are also several specimens of white granite, very like those from Mount Betty. The remaining rocks from here are richer in lime and iron, and show a series of gradual transitions from micacious granite, through grano-diorite to quartz diorite, with considerable quantities of dark mica, and green hornblende. In one of the specimens the quantity of free quartz is so small that the rock is almost a quartz-free diorite. The quartz diorites are: some medium-grained, some coarse-grained (quartz-diorite-pegmatite), with streaks of black mica. The schistose rocks from Scott's Nunatak are streaked, and, in part, very fine-grained quartz diorite schists. Mica schists do not occur among the specimens from this mountain.
Our knowledge of the geology of South Victoria Land is mainly due to Scott's expedition of 1901 -- 1904, with H. T. Ferrar as geologist, and Shackleton's expedition of 1907 -- 08, with Professor David and R. Priestley as geologists. According to the investigations of these expeditions, South Victoria Land consists of a vast, ancient complex of crystalline schists and granitic rocks, large extents of which are covered by a sandstone formation ("Beacon Sandstone," Ferrar), on the whole horizontally bedded, which is at least 1,500 feet thick, and in which Shackleton found seams of coal and fossil wood (a coniferous tree). This, as it belongs to the Upper Devonian or Lower Carboniferous, determines a lower limit for the age of the sandstone formation. Shackleton also found in lat. 85° 15' S. beds of limestone, which he regards as underlying and being older than the sandstone. In the limestone, which is also on the whole horizontally bedded, only radiolaria have been found. The limestone is probably of older Palæozoic age (? Silurian). It is, therefore, tolerably certain that the underlying older formation of gneisses, crystalline schists and granites, etc., is of Archæan age, and belongs to the foundation rocks.