PREFACE 



The publication of the second volume of the Geology of the British Antarctic Expedition 

 of 1907-1909 has been considerably delayed through several causes, chief among which 

 are the departure of Sir Ernest Shackleton on his present Antarctic Expedition and 

 above all the Great War. 



The latter has been such an obsession and has so wholly claimed the active services 

 of both of us * that it has been found to be quite impossible under the circumstances 

 to summarise and modify many of the statements in Vol. I. We must therefore be 

 content with touching on just a few salient points. 



First in regard to the Drygalski Ice Barrier Tongue and the Nordenskjold Ice Barrier 

 Tongue. In the opinion of one of us (Professor David) the sections given on Plate XIV 

 and the plate facing p. 74 are probably incorrect. Instead of both these glaciers being 

 shown as riding on an embankment of their own moraines and subglacial gravels, it is 

 probable that these glaciers are afloat for the greater part of their length, and the 

 longitudinal section, if generalised, should probably be drawn as follows : 



THE DRYGALSKI ICE BARRIER TONGUE. 



ROSS SEA 



This interpretation is suggested (1) by the few soundings around the Drygalski Ice 

 Barrier which show a depth of 300 fathoms close to the extreme end and 668 fathoms 

 at 20 miles back, shorewards, from the end of the Barrier ; (2) by the fact that Glacier 

 Tongue between Hut Point and Cape Evans, a smaller edition of the Drygalski and 

 Nordenskjold Ice Barrier Tongues, actually broke away during the earlier part of Scott's 

 last Expedition ; (3) by many interesting sections published by Professor J. W. Gregory 

 in his book on Fiords. 



Next, the question has been raised by Frank Debenham, B.Sc, one of the Geologists 

 of Scott's last Expedition, as to whether along the western side of what we have termed 

 the Antarctic Horst the marked westerly descent of the rocks is due to flexing or faulting. 

 On this point we have no definite evidence. 



The photographs with which Vol. I is illustrated are the work of several members 

 of the Expedition. In the case of many the identity of the photographer has been 



* At the eleventh hour this volume was hung up in the press on account of Major (Professor) 

 T. W. E. David and Captain R. E. Priestley being engaged on military service and too fully occupied 

 or out of touch with the printer. The undersigned is engaged in war service in England, and 

 has arranged to take over the work of passing the volume through the press. — D. Mawson. 



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