SCIENTIFIC ADVANTAGES OF AN ANTARCTIC EXPEDITION. 433 



The dredgings of the Challenger expedition brought up pieces of granite, 

 gneiss, and other continental rocks, and detritus of these materials was 

 observed to increase on the sea floor southward in the direction of the 

 Antarctic land. More recently several sealing vessels have brought 

 home from the islets of Graham Land, to the south of the South Shet- 

 lands, pieces of different varities of granite, together with some volcanic 

 rocks and fossiliferous limestones. So far as these rocks have been 

 studied they do not appear to differ from similar rocks all over the 

 globe. The granites have been found by Mr. Teall to be just such 

 masses as might have come from any old mountain group in Europe or 

 America. 



Among the specimens sent to me by Captain Eobertson, of the Active^ 

 from Joinville and Dundee islands, which form the northeastern termi- 

 nation of Graham Land, there was one piece of reddish jasper which 

 at once attracted my attention from its resemblance to the " radiolarian 

 cherts " now found to be so widely distributed among the older Paleozoic 

 rocks, both in the Old World and in the New. On closer examination, 

 this first impression was confirmed, and a subsequent microscopic study 

 of thin slices of the stone by Dr. Hinde proved the undoubted pres- 

 ence of abundant radiolaria. Tlie specimen was a loose pebble picked 

 up on the beach of Joinville Island. We have no means of telling 

 where it came from or what is its geological age. But its close resem- 

 blance to the radiolarian cherts so persistent in the Lower Silurian 

 formations of the United Kingdom raises the question whether there 

 are not present in the Antarctic regions rocks of older Paleozoic age. 



It would be of the utmost interest to discover such rocks in situ, and 

 to ascertain how far their fossils agree with those found in deposits of 

 similar antiquity in lower latitudes, or whether, as far back as early 

 Paleozoic time, any ditJerence in climate had begun to show itself 

 between the polar and other regions of the earth's surface. 



Among the specimens brought home by Dr. Donald and Captain 

 Larsen from Seymour Island, in the same region, are a few containing 

 some half dozen species of fossil shells which have been named and 

 described by Messrs. Shannon and JSfewton, who suggest that they 

 point to the existence of Lower Tertiary rocks, one of the organisms 

 resembling a form found in the old Tertiary formations of Patagonia. 

 Large well-developed shells of Cucullcca and Cytherea undoubtedly 

 indicate the former existence of a far milder climate in these Antarctic 

 seas than now prevails. 



If a chance landing for a few hours on a bare islet could give us these 

 interesting glimpses into the geological past of the South Polar regions, 

 what would not be gained by a more leisurely and well-planned expe- 

 dition'? 



But perhaps the geological domain that would be most sure to gain 

 largely from such exploration would be that which embraces the wide 

 and fascinating field of volcanic action. In the splendid harvest of 

 SM 97 — -28 



