REPORT ON ROCKS FROM WEST ANTARCTICA 



AND THE SCOTIA ARC 



By G. W. Tyrrell, a.r.c.sc, d.Sc, f.g.s., f.r.s.e. 

 Lecturer in Geology, University of Glasgow 



(With Geological Notes by N. A. Mackintosh, D.Sc, and J. W. S. Mark, M.A., B.Sc.) 



(Text-figs. 1-14) 



FOREWORD 



By J. M. WORDIE, M.A. 



In the second volume oi Das Antlitz der Erde published in 1888, and again in more detail in the final 

 volume in 1909, E. Suess put forward the view ' that the Andes are to be seen again in Graham Land '. 

 By this dramatic phraseology he implied that the folded mountain border of the Pacific, as exemplified 

 in the Andes, swings eastward from Tierra del Fuego to South Georgia and then curves back from the 

 South Sandwich Islands through the South Orkneys to Graham Land and the South Shetlands. Suess 

 based his views on a memoir by H. Reiter in 1886,^ who there gave substance to an idea put forward 

 as far back as 1831 by Sir John Barrow."^ Suess characteristically gives the credit for these arguments 

 to Reiter, whose paper I have not seen, but it is not unlikely that it was Suess himself who suggested 

 this work; the first volume of the Antlitz had appeared in 1885, and there can be no doubt but that 

 the ideas of the second volume would already have formed themselves in the author's mind, and this 

 was a problem which required to be examined. Andersson, in his Geology of Graham Land, in fact 

 mentions that Reiter had been stimulated by Suess's first volume. In the interval between Suess's 

 first statement in 1888 and his more detailed advocacy in 1909, Dr Otto Nordenskjold led the Swedish 

 Antarctic Expedition to the east coast of Graham Land in 1901-3, and J. Gunnar Andersson who was 

 with him published his important Geology of Graham Land in the Bulletin of the Geological Institute 

 of Upsala, vol. vii, Upsala, 1906. Nordenskjold himself was also much alive to the problem and has 

 both described the rocks, Petrographische Untersuchungen aus den Westantarktischen Gebiet, Upsala, 

 1906, and also put forward an authoritative statement of the whole problem in Handbuch der 

 Regionalen Geologie: Antarktis, Heidelberg, 1913. Nordenskjold and Andersson carried out in the 

 field what Reiter had sensed in the study. Andersson, Nordenskjold, and Suess together may 

 , therefore be regarded as the main advocates of 'two groups of Antilles'. 'South Antilles' was the 

 name first given to the islands of the southern arc; but more recently the sea enclosed by these 

 islands has been named the Scotia Sea, and the name South Antillean Arc has now automatically 

 been replaced by the more appropriate title of Scotia Arc. 



Andersson and Suess could base their arguments only on imperfect data, some of which are now 

 known to be incorrect. Since then many new rock specimens have been obtained and worked on 

 by qualified geologists. The activities particularly of the Discovery Committee have succeeded in 

 providing collections surpassing all previous material. Dr Tyrrell has already dealt with some of 

 the collections in earlier papers on South Georgia, the South Sandwich Islands and the South 

 Shetlands ; and in the present memoirs he is at last able to make authoritative statements on the remain- 

 ing portions of the arc either scantily known or completely unexplored at the time when Suess made 

 his great analysis of the plan of the Earth. 



1 H. Reiter, Die Siidpolarfrage imd Hire Bedeutimg fiir die genetisctie Gliedenmg der Erdoherflache, Weimar, 1886. 

 " Sir John Barrow, Journal of tlie Royal Geographical Society, vol. i (1832), p. 62. 



