BEARDMORE GLACIER 119 



by the remarkable Ice-cut shelf to tlie right of Lower Glacier Depot, and to the 

 extreme right of the photograph. This, on a larger scale, exactly I'ecalls the 

 similar structm-e noticed above the Mackay Glacier at Granite Harbour. It is 

 evidence of valley in valley structure, or an over-deepened valley on a lai-ge scale. 

 There can be little doubt that the Beardmore Glacier has formerly been so much 

 higher than it is now, that it has completely overflowed the top of Mount Hope, 

 burying it deep under ice. Mount Hope is about 2760 feet above sea-level, and its 

 summit not only bears evidence of intense glaciation, but it is strewn with a variety 

 of foreign erratics, including fragments of diabase and limestone. It is in itself a 

 magnificent glacial " flood-gauge." The stranding of these numerous erratics on its 

 surface, all of which show evidence, when not recently weathered, of intense 

 glaciation, has been due to the material being probably pushed up over the top of 

 Mount Hope rather than dropped from above on to its surface during a retreat of 

 the glacier ice. The glaciated foreign boulders, therefore, on Mount Hope are 

 conclusive proof — no better could well be had — that the Beardmore Glacier here 

 tbrmerly stood 1800 feet above its present level. It must be remembered that 

 this is a very conservative and quite a minimum estimate of the former thickness 

 of the glacier ice. This makes the former occupation of the great shelf to the 

 right of Lower Glacier Depot by the solid ice of the Beardmore Glacier not only 

 probable, but reasonably certain. This cliff", then, may perhaps be looked upon 

 as glacier-cut. 



Immediately below this shelf is evidence of a cirque. On the platform between 

 the glacial-cut high level cliff" and the great monolith of granite behind Lower 

 Glacier Depot a small corrie glacier can be seen creeping down to join the 

 Beardmore Glacier. The question here suggests itself, what was actually the 

 approximate former thickness of the Beardmore Glacier when the ice flood was at 

 its maximum ? If one sees in a progressively deepened river valley high terraces of 

 old gravel lying at, for instance, 1000 feet above the present bed of the river, and 

 observes also that the river is now forming terraces at its present level, one 

 obviously would not be justified in coming to the conclusion that the depth of the 

 old river was formerly represented by the diff*erence in level between its old gravel 

 terrace and its modern one. One might argue in such a case that depth of water in 

 the river was formerly 1000 feet. It may be the case with the Beardmore Glacier, 

 as in the illustration of the river, that since the period of maximum glaciation it has 

 materially deepened, that is, over-deepened, the original wide and comparatively 

 shallow V-shaped valley. Since the diminution of snow supplies on the plateau 

 the volume of the glacier has been much restricted, so that it has been unable to 

 work over the whole of its old floor, confining its attention entirely to the low-lying 

 portion of its pi'esent " trogtal." Again one is tempted to speculate as to whether 

 the high level glacial terraces of the modern trogtal were originally excavated 

 synchronously with the trogtal by glacier ice filling the main valley, or whether the 



