18 Dr, Forchhammer on the [July, 



necessary but to bum the slate, and to allow it afterwards to re- 

 main sufticient time exposed to the atmospheric air, that the sul- 

 phate of peroxide of iron thus formed may be decomposed by the 

 alumina and potash, and at last to dissolve the alum. This 

 slate, when so bituminous as to burn, is used as fuel in the 

 alum manufactories. Large round masses, of a pretty pure black 

 limestone, highly impregnated with bitumen (swmestone, anthra- 

 colite, Werner) occur every where in this alumslate. Round 

 balls ofsulphuret of iron and sulphate ofbarytes are likewise not 

 rare. 



The sandstone of this transition formation is distinguished 

 from that of most other countries by its composition which is 

 similar to that of granite ; felspar, and even mica, are necessary 

 to its composition ; quartz being always in the greatest quan- 

 tity. The almost absolute want of all useful metals in the whole 

 formation distinguishes it likewise from the transition formation 

 of most countries, and when compared with the primitive moun- 

 tains of Scandinavia, which almost every where contain rich iron 

 ores, which have copper in abundance in some places, rich mines 

 of cobalt and silver, and where even gold has been found on dif- 

 ferent places, such a deficiency of metals must certainly excite sur- 

 prise. For in other countries the rocks, and principally the slate 

 and limestone of the transition formation are as rich as the pri- 

 mitive rocks. In two places of the transition rocks in Scandi- 

 navia, attempts have been made to work mines of galena ; one 

 in Scaane, near Cimbrishara, and another in Norway, not far 

 from Stroemsoe, but both have failed. 



The primitive mountains when compared to those of the Alps, 

 exhibit a very material difference, both in external appearance 

 and composition. The mountain chain which separates Norway 

 from Sweden does not, at its highest point, attain 8000 feet, 

 but it surpasses on the other hand the primitive chain of the 

 Alps both in length and breadth. Its rocks are mostly such as 

 it would be difficult to say whether they are gneiss or granite. 

 From the main ridge, numerous parallel ridges of the same rock 

 extend to the Gulf of Bothnia and Baltic Sea, thus forming a 

 number of valleys and plains, which begin at the coast, and termi-^ 

 nate at the neighbourhood of the boundaries between Norway 

 and Sweden* In these plains, most of which likewise consist of 

 primitive rocks, the richest beds of magnetic iron ore are found, 

 such as at Daunemora, Haesselkulla, &c.; but it is also in these 

 valleys and plains, that the transition formation has had room to 

 expand, witn, however, this great difference from most others, 

 that it contains many crystalline rocks. These rocks of the 

 transition formation are confined comparatively to the lower 

 places, with some remarkable exceptions however, and it is a 

 very interesting fact, which we owe to the observations of Dr. 

 Wahlenberg, that each of the greater lakes of Sweden haa 

 its traasition formation, which extends in regular beds on the 



