MOVEMENT OF GLACIERS. 
83 
are caused by an overflow of Eoss Piedmont. Captain Scott found that the ice of 
such channels as Mulock Inlet pushes the piedmont-ice away from the land and leaves 
a chasm,* some 100 feet deep, in the intervals between them. At such outstanding 
points as Minna Bluff, cracks and crevasses radiate outwards, particularly towards 
the east and north-east ; but a sledge-party, by giving the land a wide berth, 
was able to avoid most of these. Near the north end of White Island also, series 
of radiating cracks are found. It would therefore seem probable that the Eoss 
Piedmont is moving northwards bodily. 
The ice-falls of Ferrar Glacier indicate movement, but, as the crevasses always 
remain drifted up with snow, the rate must be exceedingly slow. In the channel at 
the foot of Knob Head, where the evidence of up-thrust is recorded above, the banks 
of the frozen ponds have several small ridges alongside and parallel to the glacier- 
side. These ridges, which are occasionally broken along their length, indicate a 
certain amount of movement ; as this is the only spot where rupture caused by 
shearing movement is obvious, the fact is noteworthy. 
Near the sea, where the ice-tongue floats in its valley, the tide-crack follows the 
side of the glacier for a distance of at least 10 miles. Near the foot of the hill 
G 2 the crack trends towards the centre, and, gradually disappearing, is replaced by 
other cracks which trend inwards up the valley. It would seem that the point of 
replacement indicates the floating of the ice, and that the oblique cracks show a 
slightly more rapid forward movement of the mass of ice behind. 
In the amphitheatre or depression of the Ferrar Glacier, two miles from the foot 
of Knob Head, the ice shows a network of ribbon-like cracks or fracture-lines ( liisse j). 
These are often less than two inches apart, and, without opening more than a hair’s 
breadth, extend for great distances. Parties camped on this ice have observed on 
several occasions that very rapid splitting or bursting asunder takes place with 
loud report, as soon as the hills cast their shadows on the ice. The reports 
which accompany the splitting are loud and frequent, and often resemble the noise 
of independent rifle-firing. The noises frequently continue for an hour and a half at 
a time. Kupturing has also been observed at several other spots, and seems to be 
caused by strain set up by changes of temperature in the ice. That the ice is in a 
state of strain is proved by the fact that a blow from an iron-shod ski-stick has 
produced cracks which have extended 50 yards across the surface of a mass of ice 
not less than 100 feet thick. 
Snow. — The usual accumulation of snow took place during violent blizzards 
when the air became thick with fine snow-dust (Fig. 48). On a few occasions in the 
summer, however, large flakes fell gently from a cloudy sky. Sometimes soft hail in 
rounded pellets and soft woolly hexagonal snow-crystals descended from an overcast sky. 
Occasionally also, during summer, hexagonal ice-crystals up to half an inch across fell 
* Scott, Geog. Joum. April 1905, vol. xxv, p. 366, plate. 
f Drygalski, ‘ Gronland-Expedition,’ 1897, Bd. i, p. 80 ; Heim, ‘ Handbucli der Gletscherkunde,’ 1885, p. 202. 
M 2 
