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HENRY G. FERGUSON 



trough across the center of the island, where the most active of the 

 present volcanoes are now found. This seems to have been accom- 

 panied by a certain amount of subsidence, and the present top of the 

 plateau is in reality an old peneplain surface, the truncated edges 

 of the tilted lava flows reaching about the same level. In regions 

 where the dip is steeper than in the Botnsdalr, this gives a very notice- 

 able serrate appearance to the sky-hne. Whether this peneplain 



Fig. 2. — Indurated moraine on the south shore of the Hvalfjord. 



is tilted through later movements cannot be ascertained until better 

 topographic maps are available, but the surface is much broken by 

 later faulting. During this period came the extensive faulting, 

 which greatly reduced the size of the island, and later the erosion of 

 the fiords, these in part due themselves to faults. After the island 

 had assumed roughly its present shape came the flat-lying lavas 

 noted on Thoroddsen's map as "Doleritic lava (pre-glacial and 

 glacial)," and several glacial periods. The time required for the 

 peneplanation of the plateau, its uplift, and the present erosion seems 

 to furnish additional evidence that the regional basalts are Tertiary 

 in age. 



I A. Geikie, Ancient Volcanoes of Great Britain, Vol. II, p. 215. 



