ANTARCTIC ADVENTURE AND RESEARCH 



of the Ross Sea, and the islands in the vicinity of 

 Graham Land. It is a curious and gratifying fact that 

 the two locahties are largely complementary. Thus the 

 Ross area is rich in Paleozoic rocks and fossils, but 

 offers little to help in the deciphering of Mesozoic and 

 Tertiary deposits, while Graham Land has a fine 

 sequence of rocks of precisely these ages. 



Summary. — The accompanying geological sections 

 (see Figure ii) show in a somewhat generalized fash- 

 ion the main features of Antarctic geology. They are 

 both due to Sir Edgeworth David. Commencing with 

 the section across MacMurdo Sound (in East Ant- 

 arctica) we see that the basal portion of the continent 

 here consists of granites, gneisses, and other meta- 

 morphic rocks such as various schists. Probably this 

 series of rocks is more or less universal throughout 

 Antarctica. The oldest sedimentary rocks of which 

 we have much data are limestones of the Cambrian 

 Age, in which the writer was able to identify the coral- 

 loid organisms Archeocyafhincc in 1910. These fossils 

 have since been found near the Beardmore Glacier in 

 191 1 and in rocks dredged from the Weddell Sea.^ 

 Above the Cambrian limestones is a tremendous series 

 of nearly level-bedded sandstones and shales which 

 extend probably throughout later Paleozoic time and 

 quite probably into early Mesozoic time without much 

 deformation or great breaks in the sequence. This 

 is the remarkable Beacon Sandstone formation which 

 probably extends from Mount Nansen (85° S.) and 



^W. T. Gordon, Archeocyathincs from the Weddell Sea (Roy. 

 Soc, Edin,, 1920, pp. 681-714). 



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