12 GEOLOGICAL MEMOIRS. 



localities. For other particulars 1 must refer to a former paper of 

 mine * . 



Phenomena of quite an analogous character to those of Christian- 

 sand and Arendal are met with at many other Scandinavian localities. 

 With reference to this I will mention only the crystalline limestones 

 of Aker, Sala, and Tunaberg. The spinel-ruby from the limestone 

 quarry of Aker is sufficiently well known. We here also meet with 

 Garnet, Mica, Serpentine, Chondrodite, &c. The marble of Sala, so 

 rich in various minerals, contains, according to Hausmannf, Mala- 

 colite (according to H. Rose remarkable for containing a large propor- 

 tion of water), Tremolite, Garnet (rare). Quartz, Chlorite, Serpentine, 

 Talc, Asbestos, Lead-glance, Zinc-blende, Iron-pj^rites, Magnetic py- 

 rites. Magnetic iron, Copper-pyrites, &c. Still richer in minerals is 

 the Crystalline limestone of Tunaberg, of which A. ErdmannJ has 

 lately given us some veiy interesting accounts. In it there occur — 

 Garnet, Malacolite, Spinel (Pleonaste), Chondrodite, Scapolite, Coc- 

 colite, Epidote, Serpentine, Chlorite, Quartz, Amphodelite, Gillin- 

 gite, Hedenbergite, liisingerite, Graphite, Sphene, Cobalt-glance, 

 Copper-pyrites, Blende, Iron-pyrites, Magnetic pyrites. Magnetic 

 iron. Iron-glance, Molybdenum-glance, Massive Bismuth, &c. 



If we consider the geognostical and mineralogical phenomena, 

 sketched in the foregoing pages as presenting themselves in various 

 districts of Norway, to be so many links or stages in a great Transi- 

 tion series or process, we may interpolate the links or stages that are 

 wanting. We can then follow up a clay-slate and limestone forma- 

 tion from its original deposition under water to the stage in which it 

 is presented as gneiss and marble with a multitude of foreign mineral 

 contents. We see these included minerals, which now appear to us 

 not as accessories, but as belonging to the genetical conditions of the 

 rock, develope themselves from the ingredients which were in part 

 originally within the limestone and clay-slate, but evidently in part 

 also introduced at a later period. As components of the latter kind 

 we may particularly mention Fluor (in the Chondrodite, Fluor-spar, 

 Mica) and combinations of sulphur vdth metals (sulphurets of zinc, 

 copper, lead, and bismuth). 



Wliatever geological theory we may embrace, — to whatever natural 

 force we may ascribe the chief part in these operations, — we must 

 believe in a m.etaraorphosis as taking place here. The theory of 

 metamorphism has of late years taken possession of minds as well as 

 of rocks ! And indeed the primordial gneiss of Scandinavia sees its 

 privilege of aboriginality endangered ! Still we may easily go too 

 far in the Metamorphic as in the Water theory. Is there possibly 

 within the region of the so-called Primordial Gneiss more than one 

 gneiss formation ? This important question, which Keilhau raises in 

 the third part of his Gcea Norvegica (p. 367), cannot at present be 



* Leonhard und Bronn's Jahrbuch, 1843, p. 631. 



t Reise durch Scandinavien, vol. iv. p. 268. Hausmann recognized that the 

 marble of Sala is interstratified with the gneiss, whilst others had previously re- 

 garded it as lying on the gneiss. 



X Kongl. Vetensk. Akad. Handl. 1848. 



