Continental Flotation and Drift

Abstract

SINCE my return from the Falkland Islands a few months ago I have followed with great interest the course of the discussion in the columns of NATURE which has ensued upon the publication by Prof. Wegener of his revolutionary views on the flotation and drifting of continental masses. During my recent geological survey of the Falkland Islands I was very greatly impressed by the extraordinary similarity of the geology of the Islands to that of Cape Colony. The geological succession comprises rocks ranging in age from Archaean to Permo-Carboniferous, although rocks of Cambrian, Ordovician, and Silurian age appear to be absent. The oldest rocks closely resemble some of the Archaean rocks of Cape Colony; and from the Devonian to the Permo-Carboniferous the lithological and palaeontological succession is practically identical in the two areas. The post-Triassic dolerite dykes of the Falklands are also very like the intrusions of the same age in Cape Colony. The east and west folding so evident in the southern part of Cape Colony makes the most conspicuous feature in the Falkland Islands. The only notable point of difference in the two areas is that whereas in Cape Colony the lowest division of the Cape System (Devonian), namely the Table Mountain Series, is much folded, the corresponding rocks in the Falkland Islands have escaped such disturbance and lie almost horizontal, or with only a gentle dip, over an area of many square miles. The equivalents of the middle and upper members of the Cape System (Bokkeveld Series and Witteberg Series) are, however, intensely folded in the Falkland Islands.