140 
G. T. PRIOR. 
and is characterised generally by the presence in the ground-mass of patches of a 
micropegmatitic or spherulitie intergrowth of quartz and felspar. In this and other 
characters it strikingly resembles the so-called “ augite-diorite,” dykes of which break 
through the pyroxene-granulites and gneisses of Southern India. 
The sandstone-dolerite formation of South Victoria Land appears to be very 
extensive, for fragments of the characteristic dolerite were met with in most of the 
localities within the Antarctic Circle visited by the ! Discovery,’ and were found in the 
dredgings even as far north as near the Balleny Islands. 
Finally, the islands off South Victoria Land, from the Scott Islands in the north to 
the Ross Archipelago in the south, as well as Cape Adare on the mainland, and in all 
probability many of the mountains, such as Mount Melbourne, which fringe the coast 
below the main plateau, consist of volcanic rocks of comparatively recent date. 
These volcanic rocks may be regarded as belonging to one petrographical province 
characterised by the association of hornblende- and olivine-basalts approaching the 
limburgite-type, with very alkali-rich rocks of medium basicity comprising phonolitic 
trachytes and phonolites, and also alkaline-basalts or kenytes almost identical in mineral 
and chemical composition with the ancient rhomb-porphyries of Norway and the very 
similar recent lavas of Mount Kenya and Mount Kilimandjaro in East Africa. 
A striking feature in the basalts of limburgite-type is the high percentage of 
titanic acid and the number of included coarse-grained nodules, many of which are 
felspathic and gabbro-like in character. 
These volcanic rocks of South Victoria Land belong undoubtedly to the Atlantic 
group, although they occur along a coast which has been described as distinctly of 
the Pacific type.* 
* While these pages were in the press, Band II, Theil I of the Deutsche Siidpolar Expedition (1901-1903) 
was published: in No. 2, ‘Geologische Beschreibung des Gaussberges,’ by E. Philippi, the author brings forward 
arguments in favour of the view that the coast of South Victoria Land is really of Atlantic type. 
