GRANITES OF GRANITE HARBOUR AND TIIE SNOW VALLEY. 
33 
Granite Harbour (Fig. 15). 
In this harbour there is a prominent headland some 500 feet high and two miles 
long ; in form it is distinctly like a bursting cabbage. Where a landing was made 
the rock proved to be entirely granite. The rock-surface is absolutely bare of 
snow, and is weathering under desert-conditions apparently analogous to those 
described by Walther as obtaining in Sinai.* The joints tend to be platy and 
parallel to the surface, but the edges of the joint-blocks are ragged, and the curve 
is usually convex downwards. In other places the joints are vertical ; there the 
rock breaks up more rapidly, and produces talus-slopes which extend almost the 
whole height of the cliff-face. Dark circular patches, in rows which are often 
parallel to the joint-planes, are seen on the surface, and it came as a surprise to 
find that the rock is coarsely crystalline. 
The greater portion of the boss consists of a grey biotite- granite (129), and the 
larger talus-slopes always follow certain veins or dykes w r hich extend up the whole 
face of the cliff. The centres of these veins consist of a coarse piuk granitic rock 
(155) with idiomorphic crystals of red orthoclase up to half an inch in diameter, 
but within a distance of some fifteen feet these phenocrysts become paler in colour, 
the rock meanwhile becoming less porphyritic, and thirty feet from the centre it has 
graded into the ordinary grey granite of the main mass of the boss. These pink 
dykes are about one hundred yards apart ; it is noteworthy that in many cases 
the change from grey to pink is not quite gradual, but takes place in stages at 
the joint-planes, thus suggesting multiple dykes. These stages of the passage are 
marked by bands, a foot or so across, which become successively coarser and pinker 
as one passes from the sides towards the centre. 
Thin seams of micaceous schist (96), narrow black basalt-dykes (113), and 
numerous other varieties of rock, w r ere met with, and specimens of these were 
collected during our hasty scramble ashore (see p. 126). 
The Snow Valley west of the Northern Foothills. 
In the area between the Foothills and the Royal Society Range, a district 
which I have called the Snow Valley, isolated hills just raise their heads above 
the snow, and expose to view occasional masses of granite-blocks, which at first 
sight would appear not to be in situ. There are five or six of such hillocks, with 
summits about 3500 feet above sea-level, which form the watershed between the 
Blue Glacier and the ice-cascade separating the hill G 2 from the hill G 3 . 
The points p 1; 77.,, etc., on the map indicate the positions of these hillocks, but 
of the four only ij 2 was visited ; it proves to consist of grey hornblende-biotite- 
granite (561, 562). The mass exposed is about 100 yards long, and rises 200 feet 
VOL. I. 
Walther, Abhand. math.-phys. Cl. d. k. sachs. Ges. Wiss., 1891, Bd. xvi, p. 364. 
F 
