398 PROF. OLAE HOLTEDAHL ON THE [vol. lxxvi, 



In Jemtland we find in places metamorphosed sedimentary rocks 

 lying above so late a zone as the Silurian Pentamerns Limestone. 

 Even if the greater part of the metamorphosed rocks of this 

 region is not of the age of the Sparagmite Division, as Tornebohm 

 assumed, but younger, they may well be considered to be older 

 than the above-mentioned Silurian horizon. Probably, as has 

 recently been held by the Norwegian geologist C. W. Carstens, 1 

 who has made extensive studies in the Trondhjem district, much 

 of the ' Seve Group ' in the Trondhjem- Jemtland region is of 

 Orel o vie ian age. 



Jn fact, it seems to be increasingly evident that the meta- 

 morphic sedimentary rocks of the central and northern part 

 of the mountain-belt of Scandinavia are chiefly of Ordovician age. 

 The remarkable likeness between the 'mica-schist-marble group,' 

 making up the sedimentary portion of the solid rock-formations 

 of the western part of Northern Scandinavia, and the ' Heclahook 

 System ' of Spitsbergen, which system must now be considered to 

 cover early and middle Ordovician time, 2 is in this connexion a 

 point of fundamental importance. Just as more and more of the 

 gneiss and granite-masses of Northern Norway during later years 

 have proved to be Caledonian intrusive and not Archaean rocks, the 

 huge mass of gneiss and granite making up the north-western 

 corner of Western Spitsbergen, and previously regarded as Archaean, 

 is now known to represent intrusions of igneous masses during the 

 Caledonian deformation. 3 



In the map of the Scandinavian Peninsula published in Torne- 

 bohm's previously-mentioned Gruide-Book (No. 1) of the Stockholm 

 International Geological Congress, the greater part of Northei'n 

 Norway was mapped as Algonkian Seve rocks, and Archaean 

 granites. 



Only for a single, yet far from unimportant, part of the Scandi- 

 navian region of strong deformation the actual conditions seem to 

 show that the thrust-masses consist mainly of rocks belonging to 

 the Sparagmite Division, and thus are older than the fossiliferous 

 Lower Cambrian. This is the case along the southern, possibly 

 also parts of the eastern, border of the Sparagmite region of Central 

 Southern Scandinavia (see fig. 1, p. 388), the region where the true 

 Sparagmite Division primarily existed, the exact northern border of 

 which, however, is unknown to us. The fact is that some of the 

 'Sparagmites ' (of, for example, Jemtland) probably represent rocks 

 that are younger than the Lower Cambrian, and therefore do 

 not belong to what should be called the ' Sparagmite Division. 7 

 This later age of certain widespread Swedish Sparagmites and 

 cpiartzites has recently been advocated bj G. Frodin. 4 



1 ' Oversigt over Trondhjemsfeltets Bergbygning ' Kgl. Norsk. Vidensk. 

 Skrift. 1919, No. 1. 



2 0. Holtedahl, ' On the Pakeozoic Series of Bear Island, &c.' Norsk 

 GeoL Tidsskrift, vol. v (1919) pp. 138-41. 



:i O. Holtedahl, ' New Features in the Geology of North-Western Spits- 

 bergen ' Amer. Journ. Sci. ser. 4, vol. xxxvii (1914) p. 415. 

 4 Sveriges Geol. Undersokn. ser. C, No. 299, 1920. 



