FOSSIL FORAMINIFERA FROM THE BURDWOOD BANK 15 



South Georgia with its folded Cumberland Bay Series, probably in part at least of 

 Cretaceous age, is part of the same arc of folding.^ 



The very numerous echo-soundings taken by the Discovery Expedition have been 

 studied by H. F. P. Herdman,^ and the results are of great importance from the geo- 

 logical standpoint. It appears now to be clear for the first time that the contour of the 

 sea-bottom definitely fits in with the line of the Scotia Arc from Tierra del Fuego, 

 through Burdwood Bank, Shag Rocks, South Georgia, Gierke Rocks, South Sandwich 

 Islands, South Orkney Islands, to the South Shetland Islands and the Trinity Peninsula 

 of Graham Land.^ This trend is clearly marked on the new charts by the ridge, 

 frequently irregular, which rises from the sea floor and, it seems, must reflect the 

 geological fold structure. An equally important point is that there appears to be no 

 room for any alternative arc, since the available soundings are set too close to allow of 

 any appreciable ridges across the Scotia Sea farther west having been overlooked. 



What may have been two abortive attempts to shorten the arc by closure farther west 

 are perhaps indicated by, firstly, the south-eastward projection of the eastern end of 

 the Burdwood Bank, which has no mapped counterpart on the south of the arc; 

 and secondly, by the position and trend of South Georgia, which has a counter- 

 part on the south of the arc indicated by the northerly double projection of the 

 3000 m. line. In neither case, however, can the ridges be regarded as more than a 

 tentative eff'ort of the folding, which never arrived at completion. In the former case, 

 indeed, the projection is towards an area of greater than the usual depth in the Scotia 

 Sea. 



For suggestions and criticism of this paper I am much indebted to Dr Stanley Kemp, 

 F.R.S., to Mr J. M. Wordie, and to Mr A. G. Brighton; and for much help in the 

 determination of some of the Foraminifera I am greatly indebted to Mr A. Earland. 



SUMMARY 



Three bottom samples dredged by the Discovery Expedition yielded fossil Fora- 

 minifera of rather deep-water facies; some were obtained loose on the sea-floor and 

 others were washed in the laboratory from fragments of green-grey shales, which also 

 contained a few Radiolaria. Thirty-four species are recorded and six are figured, none 

 is new; they include some considered to be of Upper Cretaceous (Senonian) age, and 

 others probably from the Lower Tertiary. Previous records of the fossil Foraminifera 



1 For recent discussions of this see O. Holtedahl, 1929, On the Geology and Physiography of some 

 Antarctic and Sub-Antarctic Islands, Set. Res. Norwegian Ant. Exps., 1927-8, 1928-9, No. 3, pp. 104-17. 

 8vo, Oslo; and also O. Wilckens, 1932, Der Bogen der Siidlichen Antillen (Antarktis), Sitz. Naturw. Abt. 

 Nieder-rhein. Ges. Naliir- iind Heilkunde, 1 930-1, herausg. v. d. Naturhist. Ver. preuss. Rheinlande und 

 Westfalens, pp. 1-14 (separate), Bonn. 



^ H. F. P. Herdman, 1932, Report on Soundings taken during the Discovery Investigations, 1926-32, 

 Discovery Reports, vi, pp. 205-36, pis. xlv-xlvii, Cambridge. 



^ Cf. T. Stocks, 1932, Zeitschr. Ges. Erdkunde, Berlin, pp. 198-208. 



