GLACIER TONGUE 103 



under glacier ice. The southern and south-western slopes of Erebus are also still 

 being heavily glaciated, but the north-west slopes of Erebus are almost free from 

 glacier ice.* 



Since the retreat of the Eoss Barrier back to its present edge, to the south of 

 Cape Armytage, the glaciers radiating from the south-west slopes of Erebus have 

 invaded the vacated territory, cutting through the old marginal moraines of the 

 Ross Barrier, and forming later moraines. These are built up partly of fragments 

 of kenyte lava, partly out of redistributed material of the old marginal moraines of 

 the Ross Barrier. 



We may commence with the most active glaciers examined by us, viz. those on 

 the south-west slopes of Mount Erebus, extending as far south as Glacier Tongue. 



Glacier Tongue. Glacier Tongue is a very remarkable instance of a glacier jetty 

 on a comparatively small scale. It is about 5 miles in length from east to west, 

 and from a quarter to about three-quarters of a mile wide from north to south. 

 Its surface is slightly convex, rising from its seaward end eastward to its point of 

 attachment to the land. At the point where our depot for the southern journey 

 was established on it, a little over 1 mile east of its western extremity, it was 

 between 40 and 50 feet above sea-level at the highest points observed. The 

 material of which it is formed is true, blue, glacier ice. This was found to be 

 crevassed for at least 4 miles outwards from its point of attachment to the land. 

 On its north side Glacier Tongue is levelled up by the drift snow carried by the 

 south-easterly blizzards, this being of course the weather side of the Tongue. On 

 its northern or leeward side the Tongue terminates in a low cliff, frequently with 

 ovei'hanging snow cornices. Its northern wall is deeply indented at intervals so as 

 to form natural small docks, and advantage was taken of this by the Nimrod's party. 

 It was found possible to warp the ship close up to the cliff by ice anchors, and she 

 could ride out the fiercest blizzard here in comparative safety. The accompanying 

 illustrations show the appearance of this cliff late in February 1909. 



During the winter months this low cliff, for the most part, is completely masked 

 by sloping drifts of snow ; as summer thaw proceeds, and the ice breaks up, the 

 foundation of sea ice under the drifts cracks up, and carries the overlying consoli- 

 dated snow-drift out to sea, until eventually a low vertical cliff is left, as shown in 

 the photograph. "NVe thus see repeated on a smaller scale the same phenomena at 

 Glacier Tongue as those already described at the Nordenskjold Ice Barrier Tongue. 

 The accompanying sketch after H. T. Ferrar (Fig. 44) shows the shape and situation 

 of Glacier Tongue. 



Two questions of special interest suggest themselves in regard to Glacier Tongue. 

 First, what is the source of supply of its ice ? Second, is it aground or afloat ? 



In regard to the first question, it may be stated that the width of the land at the 



* It was for this reason that that portion of the mountain was selected as the route for the 

 ascent of March 1908. 



