THE GEOLOGICAL HISTORY OF SOUTH VICTORIA 



LAND 



BY F. DEBENHAM, B.A., B.Sc., Assistant Geologist to the 



Expedition 



IT is now nearly fifteen years since the first landing was made on 

 the mainland of South Victoria Land, since which time four sci- 

 entific expeditions have visited it and returned with geological 

 information. This has been, or is being, published in the form 

 of reports of a more or less technical character. Therefore it 

 seems advisable that an attempt should be made to condense this 

 information into a popular narrative of what actual changes that 

 area has undergone in past time, so far as they are known. 



The tale must necessarily be incomplete, for the difficulties 

 confronting geological investigation in those regions are natu- 

 rally considerable, but enough has been done to warrant a pre- 

 liminary interpretation of the known facts. 



South Victoria Land at the present day is marked on the map 

 as a strip of coast running in a southerly direction from Cape 

 Adare (Lat. 71) and merging into King Edward VII Plateau 

 in the region of the Beardmore Glacier (Lat. 83 85). As ap- 

 pears in the physiographic account, it consists for the most part 

 of a high level plateau terminated along the coast by steep escarp- 

 ments, more or less indented by the action of huge overflow gla- 

 ciers. It includes several groups of volcanic islands, the chief 

 of which is the Ross Archipelago (Lat. 77-79). But in this 

 narrative we shall include the Ross Sea and the Great Ice Barrier 

 in the region, as inseparably bound up with Victoria Land in its 

 history. 



The oldest rocks met with in South Victoria Land, forming 

 its foundation, or ' shield,' consist of gneisses, schists, quartzites, 

 and crystalline limestones, much altered and folded by later earth- 

 movements. On account of this alteration, much of their story 

 is hidden from us, but we may compare them in age with the 



