88 
II. T. FERRAR. 
honeycombed to a remarkable extent. The boss of trachyte above Cape Crozier, the 
kenyte of Cape Royds and basalts of other areas, show similar wind-effects. 
The Beacon Sandstone of the Royal Society Range, likewise, was almost free 
from the fine disintegration -products, particular beds being often bare for lengths 
of a mile or more. The loose quartz-grains derived from these seem only to 
remain in crevices or below projecting rock-shelves. Dolerite-columus, too, are quite 
smooth, and are coated with a bright chocolate-coloured crust (670) rarely more 
than one-eighth of an inch thick. 
Hollowed granite-boulders (Fig. 16, p. 34 ; Fig. 50) were observed at the foot 
of Royal Society Range near Descent Pass, and two types may be distinguished. 
(a) In fairly normal granite. The rock (555, 556) is a grey to pink granite 
with felspars usually about a quarter 
of an inch long ; it appears to be 
quite fresh even on the surface, and 
has a marked superficial glaze on 
both convex and concave surfaces. 
The most striking cavity is on the 
south and weather-side of a large 
block and therefore faces away from 
the sun ; it is about eighteen inches 
across at the opening, and the 
diameter increases inwards to at 
least two feet. The depth of the 
cavity is a little more than a foot, 
and the back wall is partially covered 
with a hard mamillated or botryoidal 
crust (554), consisting mainly of 
calcium carbonate, the surface being 
white, and harsh to the touch. The 
crust was lamellar, scarcely more 
than one-eighth of an inch thick, but the projecting botryoids, which are sometimes 
partially hollow, may be more ; it was firmly fixed to the granite-face, so that it 
was impossible to decide whether the surface beneath was or was not glazed. 
(b) In a very coarse granite containing abundant large crystals of orthoclase. 
The hollowed blocks (557, 558) are rounded, but the surface, owing to the rapid 
disintegration, is roughened rather than glazed. The largest cavity is in a block 
6 feet by 4 feet by 4 feet, which is hollowed almost to a shell. The cavity is 
four feet long, three feet deep, and two feet high, and has four apertures varying 
from a foot to eighteen inches in diameter, one on each side of the block. The lip 
of the apertures is exceedingly sharp, the angle being certainly not greater than 
30°. No incrustation was seen on the walls of this cavity, but on the floor is a 
Fig. 51. — Saline Pond in Moraines on west side op 
McMordo Sound. 
