THE HEART OF THE ANTARCTIC 



Great Barrier cliff terminates in high-pressure ridges 

 against Cape Crozier, the easternmost point of Ross 

 Island. 



Ross Island with its towering volcanic cones rises like 

 some vast castle at the end of this huge white wall. It 

 is formed of four large volcanic cones, Mounts Terror, 

 Terra Nova, Erebus and Bird. The three first volcanoes 

 appear to be situated on an east and west line of fracture. 

 Another fracture line probably passes in a southerly direc- 

 tion from Mount Bird tlu-ough Mount Erebus. Thus, 

 Erebus may be said to be at the junction of two important 

 systems of earth fracture. Still further south several 

 smaller craters are situated on what may be termed the 

 Erebus Fracture Zone, including that of Crater Hill, 

 near Hut Point, the winter quarters of the Discovery 

 expedition. Still further south are the volcanic islands. 

 White Island and Black Island, and somewhat to the 

 south-south-west Mount Discovery with the long volcanic 

 promontory trending from it to the east-south-east, known 

 as Minna Bluff. 



In the gaps between these islands and promontories 

 the mass of the Great Barrier moves slowly, but surely, 

 seawards towards the narrow south-westerly prolongation 

 of Ross Sea known as McMurdo Sound. Pressure ridges 

 of ice in this part of the Great Barrier, as well as actual 

 measurements taken, prove that this part of the Barrier is 

 moving seawards, both to the west and to the east of Boss 

 Island. 



McMurdo Sound is bounded on the south by the low 

 terminal cliff of the Great Barrier only a few feet in 

 height. This low ice cliff extends westwards across 

 McMurdo Sound, for a distance of about thirty miles, 

 to the magnificent coast range of Victoria Land. Majes- 

 tic peaks of gneiss, granite, sandstone and limestone 

 capped by eruptive rocks rise almost sheer from the coast 



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