GEOLOGICAL OBSERVATIONS 



Islands, and after exploring Palmer Archipelago and 

 Gerlache Strait wintered at Wandel Island. An interest- 

 ing and detailed account of the geological specimens col- 

 lected has been given by Dr. E. Gourdon.* Amongst the 

 rocks described are hornblende granites, quartz diorites, 

 uralitic gabbros, trachyandesites with hornblende and 

 mica, dacites and andesites with associated tulFs, labra- 

 dorite rocks, diabase basalts, micro-granites with pyroxene 

 and soda-hornblende. He also describes crystalline schists, 

 quartzites and quartz veins. 



Dr. Gourdon concludes that these rocks are part of 

 the eruptive series of the chain of the Andes. Nordensk- 

 jold is of the same opinion in regard to the eruptives of 

 Graham Land. 



In the South Orkneys fossil graptolites, associated with 

 radiolarian jaspers, were discovered by Bruce's expedi- 

 tion. These prove the existence there of older palseozoic 

 rocks, considered to be of Ordovician age. As far as we 

 can learn there is as yet no evidence of the presence, in 

 that region, of rocks older than Ordovician, unless some 

 of the crystalline rocks of south-western Graham Land, 

 such as those of Borchgrevink Nunatak, &c., antedate 

 that period. 



The abundant fossil plants discovered by Nordensk- 

 j old's expedition at Hope Bay, at the north-eastern end 

 of Graham Land, show that in that region, now continu- 

 ously covered with ice and snow, there existed in Jurassic 

 times a rich and diversified flora embracing ferns, cycads 

 and conifers. Amongst the plants found at Hope Bay 

 the genera Sagenopferis, Thinnfeldia, Cladophlebis, 

 Pteropliyllum, and Otozamites have been recorded as well 



* Expedition Antartique Francaise, ] 903-05, commandee par le 

 Dr. Jean Charcot. Sciences Naturelles; Documents Scientifiques 

 Geographic Physique — Glaciologie, Petrographie par E. Gourdon, 

 Docteur-es-Sciences de I'Universite de Paris. 



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