Woinii. —I'ctrnloi/ical Nofex on South Victoria Land Rocks. 485 



Sultan's Head. 



Sultan's Head, 1. — Olive-brown tuff, rather soft. A typical palagonite 

 tuft' ; the grains arc subangular, and a few present spheroidal structure. 

 In places a vesicular form in the original material is evidenced. A little 

 calcite here and there, and much colourless cementing-material, which is 

 not quite isotropic. A variety of the basalt tuff from Sultan's Head de- 

 scribed on page 109 of the official report. 



Sultan'' s Head, 2.— Specimen showing passage of olive - brown tuft" 

 (Sultan's Head, 1) into volcanic agglomerate with this material as a base 

 and considerable included fragments of dark basalts. 



Sultan's Head, 3. — Small specimens of grey pumiceous rock. The inte- 

 riors of the gas-cavities highly glazed. A highly vesicular rock, pale-grey 

 base not quite isotropic. Fragments of both quartz and feldspar, the 

 former with small fluid inclusions, none of the feldspar twinned. A little 

 granular magnetite. Pumice. It is not certain that this occurs here i'n 

 situ. 



Mount Erebus. 



The base of this mountain to the west of the Ridgeway seemed to be 

 composed almost entirely of kenyte. The larger exposures of Skuary 

 Point, Cape Barne, and Cape Royds had other rocks in addition, the last- 

 named with a copious sprinkling of blocks of granite. No. 1 specimen 

 was taken from the sea ice immediately below a small exposure some few 

 feet above sea-level, from which it had obviously fallen. This exposure 

 was on the side of Mount Erebus, but only a few yards from the origin of 

 the Ridgeway. 



Erebus, 1. — Reddish-brown rock, compact base. Numerous tabular 

 feldspars, water-white, with visible inclusions of groundmass. The planes 

 of all these feldspars are approximately parallel, and thus on one surface 

 they give lath-shaped sections, averaging about 12 mm. by 1-5 mm. The 

 rock is also slaggy, and contains gas-cavities flattened and elongated parallel 

 to the planes of the feldspars. While quite fresh it is thus very friable. 

 The groundmass brown, apparently glassy, with brown and black dusty 

 inclusions ; contains numerous lath-shaped feldspars. In some cases these 

 are invaded along the centre from either end by black dusty material, which 

 shows somewhat elongated forms under high power. The larger crystals 

 of anorthoclase contain numerous inclusions of groundmass, arranged m 

 zonal fashion, and the crystals show between crossed nicols slight local 

 differences of tint which mark out zones exactly corresponding to the in- 

 clusions. The olivine crystals are pale green, and usually accomplish clear 

 crystal outline over rather more th -n one-half of their circumference, being 

 invaded elsewhere by prolongation of the groundmass, severed inclusions 

 of which are also common. Nepheline is rather prominent in some parts 

 of the slides, and in one place is associated with an olivine crystal. Trachy- 

 dolerite, akin to kenyte, 



Erebus, 2. — A compict grey rock of close texture, with slight tendency 

 to cleave in flakes. Numerous tabular feldspars, mainly but not entirely 

 in parallel planes. These give lath-shaped sections up to 25 mm. in length, 

 and are 2 mm. in breadth. A comparatively pale ground, considerably 

 darkened, however, by fine granular magnetite. Much looks like a brown 

 glass, but no part is actually isotropic. There are numerous small feldspar 

 laths. The larger feldspars are striated with alternate narrow and wide 

 bands ; the largest show zonal structure between crossed nicols, and small 



