DYKE-ROCKS OF THE NORTHERN FOOTHILLS. 
27 
and dark veins of a doleritic rock (56G) make an angle of about 30° with them. 
From the floor of the Snow Valley, the snow sloped steeply up to the rock- 
face at an inclination which was too great for us to get the sledges up. 
Leaving these at the bottom of the slope for a couple of hours, a very risky 
proceeding when no landmarks are available, we obtained specimens without mishap. 
The fault-face on the Northern Foothills is more obvious than on the Southern ; it 
is brought into prominence by the fine, bare and apparently glaciated peak (g), which 
rises over 4000 feet high. 
Half-way down the Blue Glacier. 
Working down the Blue Glacier, Dr. Iyoettlitz collected somewhat similar 
specimens from a hill 5 miles east of G 4 ; here, as nearer G 4 , the bedding-places 
dip to the E.S.E., and the dark 
veins cut across the strike to 
the E.N.E. On this hill one of 
the structure-lines is remarkably 
prominent and suggests a thrust- 
plane, but no difference in the 
characters of the rocks on the 
opposite sides of the line was 
obvious to the naked eye. The 
specimens collected by Dr. 
Iyoettlitz in this neighbourhood 
include dioritic dyke-rocks (572, 
The north-east end of the Blue Glacier. 
At G 4 , the most south-eastern of the Northern Foothills, the arrangement of the 
rocks is well seen from a distance. Here, however, the rock is so planed down by 
ice-action that the rapid alternations of dark dyke-rocks and light-coloured limestone 
are rendered evident. The dykes crossing the brow of the hill are plainly visible 
from the glacier. A dyke of kersantite (579, see p. 130), 20 yards wide, cuts the 
crystalline limestone (575, 570). The hill is 4000 feet high ; the snow wraps its base 
and reaches quite up to the 1000-foot contour. Here again the sledges had to be 
left more than a mile away from the exposure. On this occasion, owing to the snow- 
storm that began during our absence, they were difficult to find when we returned. 
The right hank of the Ferrar Glacier , between G 2 and G ;! (Plate I\ ). 
The Northern Foothills, as stated above, form a rectangular mass with the north 
side some 12 miles long, forming the terminal portion of the right bank of the Ferrar 
E 2 
574) and a schist (570) 
Fig. 12. — The Crystalline Limestone on the north side of 
the Bloe Glacier, at G,. 
