4 io SCIENCE PROGRESS 



There is also evidence of the overthrusting across Westerbotten, 

 between Norrbotten and Jemtland. The overthrust can indeed 

 be traced from 6g° N. lat. in Norwegian Lapland across seven 

 degrees of latitude in Sweden, till the line recrosses the frontier 

 and continues for 150 miles farther into Norway. Its course in 

 Southern Norway was traced by Tornebohm across the valleys 

 of the Glommen, of Gudbrandsdal, Espedal, the Valdres valley 

 (Hedal), and Hemsedal. His conclusions were supported by 

 Reusch's 1 description of the country around Vangs Mjosen and 

 Slidre, in the upper part of the Valdres Valley, where the 

 Archean granites are overthrust over phyllites and quartzites 

 assigned to the Cambro-Silurian. And the course of the great 

 overthrust has been continued westward round the Sognefjallen 

 to the Hardangerfiord, by the work of Reusch, Rekstad, and 

 Bjorlykke, 2 and by Rekstad in the Hemsedalfjallen. 3 



The Scandinavian overthrust is therefore on a colossal scale. 

 It follows the main mountain chain of Scandinavia throughout 

 its entire length. Its length, according to Tornebohm, is about 

 1,800 kilometres (over 1,100 miles). It is therefore on a much 

 larger scale than in Scotland, where the length of the overthrust 

 from Glenelg to its northern end at Whitten Head is about 

 100 miles. The width of the overthrust is even more startling. 

 Tornebohm claims that the overthrust masses, which are still 

 1,500 metres thick, have travelled eastward for a distance of 

 eighty miles. He remarks that "such an immense width is 

 something never yet precedented in the annals of geology, 

 and he does not conceal from himself the fact that its possibility 

 will be generally doubted. But after many years of investiga- 

 tions he has come to the conviction that only by such a great 

 overthrusting can the actual relations be explained ; so he is 

 not afraid to express this conviction boldly." Tornebohm 

 claims that the width of the overthrust is not disproportionate 

 to its length. The demand made on the strength of the rocks 

 is, however, at first staggering; so it is not surprising that the 

 development of the overthrust hypothesis in Scandinavia met 

 with some opposition. 



1 Hans Reusch, " Hoifjeldet mellem Vangsmjosen og Tisleia (Valdres)," Norges 

 Geol. Undersog. No. 32 ; Aarbog for 1900, pp. 45-88. 



2 " Fra Hardangervidden," Norges Geol. Undersog. Aarbog for 1902, No. 2. 



3 Ibid. 1903. The south-western extension of the overthrust has been described 

 Dy Tornebohm, " Om den skandinaviska fjallkedjans sydvestande," Geol. For. Fork. 

 vol. xxv. (1903), pp. 282-8. 



