KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 29. N'.0 4. 127 



structurallj somewhal from the previously described granites of the region and was 

 >i: Geee considered older than fche schists of the Vestan å-region. I< sometimes occurs 

 dternate bedding with a fine-grained grej' gneiss which much resembles the common 

 •grained gneiss of the district. This phenoraenon is probably due to the intrusion of 

 granite, now transforraed into granite-gneiss», into the older schists of the comtnon 

 ss of the region, bu1 the question i Is further study. 



On the relation of contact-metamorphism and dynamo-metamorphism in the 

 Vestanå region. 



All (lie rocks in the region studied show more or less the effects of pressure. But 

 these effects are gener; ill)' slight, and strongly dynamo-métamorphosed rocks are only 

 found locally. The effects of contact-metamorphism on the contrary have a general di- 

 stribution among the rocks of sedimentary origin and even in most of the highly dynamo- 

 metarnorphosed rocks a primary structure, due to contact-metamorphism, may be recognized. 

 Onlj* the rocks of the quartzite belt form an exception, as in them no trace of a pri- 

 mary structure is preserved, still they may have had a contact structure, that now is 

 destroyed. As the granites are as much dynamo-metamorphosed as the older sedimentary 

 rocks, it is evident, that the granites and the contact-metamorphism are older than the 

 whole or at least the låter part of the tectonic movements, that raised and folded the 

 schists of the region. 



Through this folding a small part of the once widely extended quartzite formation 

 with the highest member of the gneissic series below it, the one that is least meta- 

 morphosed and in which the characteristics of an oi^iginal quartz porphyrite tuff can still 

 be recognized, were pressed clown between the deeper seated and more highly meta- 

 morphosed gneisses and thereby saved from being swept awa}^ by erosion. 



