46 
H. T. FERRAR. 
valley-bed here also is Hat and free from ice ; it is strewn with boulders of all sizes, 
and is therefore exceedingly rough. The breadth is less than twQ miles, but near 
the mouth, where it is joined by the smaller valley, it widens, and together they 
open out into the main depression of the Ferrar Glacier. ' 
The Beacon Sandstone on the north side of the smaller valley is most 
accessible at a spot west of b 2 , where the usual sandstone is capped by dolerite. 
About 300 feet are exposed, and the beds can be traced horizontally all round the 
left side until cut ofl' by the dolerite of the hill x. The main mass of x is dolerite, 
but a small exposure of sandstone is visible at its western foot. In the middle 
of the mass there are two other narrow strips of sandstone, each about 20 feet 
thick and half a mile long, which seem to have been caught up by the intrusion. 
At the west foot of this hill the Beacon Sandstone shows a new feature, for on the 
under side of a large block there was a six-inch bed composed of angular quartz- 
fragments (681). These pieces of quartz are fairly regular, almost cubic, and about 
an inch long. They are set in a matrix of the usual sandstone, and it is worthy 
of note that no rounded pebbles were here observed. 
There are four very prominent buttresses south of x, which form the sides of 
the larger valley, and in each of the buttresses two bands of yellow rock and two 
of brown rock were seen alternating regularly. These alternations possibly represent 
parts of once continuous intrusions of dolerite which follow the same bedding-planes 
across the whole area. A similar arrangement also holds in the buttresses of the 
eastern valley wall. 
The Beacon Heights (B 4 , B 3 ) (Plate V, and Section I, Plate VII). 
On the western side of Beacon Height West (B 4 ) there is a small outcrop of 
the Beacon Sandstone. This, as before, has horizontal bedding-planes. The bulk 
of the rock is coarse, even-grained in texture, and almost white in colour. The 
greater part of the mountain appears to consist of sandstone, for the lower 2000 feet 
shows a yellow rock, with horizontal joints or bedding-planes, where the even 
covering of dark talus-products is wanting. The summit is a small cap of brown 
rock, which is separated from a larger mass of the same brown rock by a band of 
yellow about 500 feet thick, also bedded horizontally. The larger mass of brown 
rock is continued in the summit of B 3 , and even extends to the summit of Knob 
Head Mountain further to the east. 
The sandstone crops out as a small cliff on the side of this mountain (B 4 ) ; there 
the cylindrical rugosities (see p. 43) are again developed and appeared to be quite 
similar to those observed on West Groin. This outcrop was traced for a distance 
of a quarter of a mile along the hillside, and the cliff is on an average 50 feet 
