TKK AIICII r.\ .;:, 



between the general structure of Scandinavia and that of Scotland, 

 but the overthrust sheets in the former region are on a imi<-h larger 

 scale, and appear to include a larger number of formations, 

 over there is this great difference between the two regions, that the 

 forces producing the thrusts have acted from opposite direct inn.. 

 i.e. from the east in Scotland and from the west in Scandinavia ; 

 so that in the latter case the unaltered rocks are found in the area* 

 which lie to the east of the overthrust tracts, i,e. in Sweden and 

 Finmark. 



The large areas occupied by Archaean rocks in the Fenno- 

 Scandiau region are partly shown in Fig. 10, which, however, does 

 not include the more eastern districts. The Swedish and Finnish 

 geologists 34 now recognise no less than four series or systems of pre- 

 Cambrian rocks : (1) a fundamental complex which is comparable 

 with the Hebridean of Scotland ; (2) the Kalevian, which is a series 

 of altered sediments and volcanic rocks ; (3) the Jatulian (princi- 

 pally quartzites) ; (4) the Jotnian and Sparagmite sandstones, which 

 seem to correspond with the Torridonian of Scotland. 



The fundamental rocks are gneisses of several kinds, some being 

 granitic gneisses which seem to be deformed and foliated granites ; 

 another type is the garnetiferous gneiss which is regarded as a 

 combination of stratified gneiss (paragneiss) and gneissic granite 

 (orthogneiss) ; while there are also banded grey gneisses (coarse and 

 fine) and some red granitoid gneiss. 



Above these gneisses, and apparently in stratigraphical sequence, 

 is a sedimentary series which in Sweden is called the " Porphyry- 

 Leptite " Group. This consists of mica-schists, green schists, lej>t iu-> 

 ( = altered felspathic tuffs), schistose porphyrites (lavas), crystalline 

 limestones, and iron ores ; these rocks occur in regular bedded 

 succession and alternation, but the bedding- planes are nearly 

 always vertical, and the rocks themselves are crystalline. The 

 series seems to be comparable with that of Loch Maree and 

 Glenelg, but is on a much more extensive scale. 



In parts of Lapland, Finland, and Olonetz (Russia), Dr. Seder- 

 holm has separated another series of metamorphosed sediments 

 under the name of Kalevian (see Fig. 10), which he regards as : 

 than the Dalecarlian porphyrites and yet clearly older than the 

 Jatulian. This series consists mainly of quartzites which ar. 

 micaceous, and pass into muscovite-schista ; they also include bands 

 of conglomerate and occasionally of talc-schist and dolomite. There 

 are also intercalated sheets of metabasite (t.. epidiorite). 



This series has not yet been identified in Sweden, bir 

 Sederholm thinks it is included in the greatly folded and plicated 

 complex of Northern Sweden, while in the south (Smaland) there 



