THE SVINAFELL LAYERS 



387 



IntergJacial. As to the intricate question, where to place the first reversal of 

 magnetism in relation to the Pleistocene climatic chronology, we have on 

 one hand Hosper's and Einarsson's observations on Snaefellsnes, which 

 indicate that this reversal did not occur earlier than the end of the Giinz- 

 Mindel Interglacial. On the other hand, the reversal took place long before 

 the deposition of the Svinafell layers, as the basalts of normal polarity 

 underlying them are greatly eroded and that erosion is probably by glaciers. 

 From a study of all the evidence it seems most reasonable to conclude that 

 the first magnetic reversal occurred towards the beginning of the Mindel 

 Glacial. 



Table 2 

 Pollen Counted in Interglacial Sediments in Iceland 



* According to Askelsson, 1938, p. 312. 

 t According to Lindal, 1939, p. 269. 



COMPARISON BETWEEN THE FLORA OF THE SVINAFELL 

 LAYERS AND OTHER INTERGLACIAL DEPOSITS IN ICELAND 



Plant-bearing deposits regarded as interglacial have been described from 

 the above-mentioned Brimlarhofdi (Stodin) on Snaefellsnes (Askelsson, 1938, 

 1960), from Bakkabrunir in Vididalur, north Iceland (Lindal, 1935, 1939), 

 and from Ellidavogur near Reykjavik (Thorkelsson, 1935; Love and Love, 

 1956). Common to the sediments in Brimlarhofdi, Bakkabri'mir, and Svina- 

 fellsfjall is the dominance of Alnus viridis as shown in Table 2. The occurrence 

 of conifer pollen in layer H in Brimlarhofdi is somewhat suspect. Askelsson 

 seems to be doubtful whether to interpret it as secondary or not; the present 

 writer is inclined to regard it as secondary. As to the age of the Bakkabrunir 

 formation, opinions differ. Lindal and Askelsson regard it as interglacial. 



