16 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 3, 



buckets to depths of 80 and 100 fathoms, nothing is to be observed 

 that can authorize the separation of the rocks in which they occur from 

 the primary or azoic class. At the same time it must be stated, that 

 crystalline white limestone, partially used as a flux, folds over here 

 and there in the irregular contortions of the mass, and seemed to 

 me to he cut hy the veins of magnetic iron, some of which are ninety 

 feet wide. These iron masses vary, containing from 40 to 80 per 

 cent, of the metal. The chief vein has a devious direction from 

 N.N.E. to S.S.W., and hades 70° to the W.N.W * 



The mines of Bisberg near Sater occur in what M. Erdmann 

 terms a mica schist composed chiefly of quartz and mica, though 

 much felspar rock also appears. Judging from the splendid open 

 cuttings or chasms from whence the magnetic iron has been ex- 

 tracted, and also from the appearance of laminae of deposit in the 

 ore, my first impression was that the ore laid in beds which strike 

 with the strata from N.E. to S.W., and dip to the S.S,E. at 80°. 

 But after all it seemed impracticable by slight observation to deter- 

 mine that these are true beds of ore ; for in following the mass un- 

 derground (which we did not), it may, I apprehend, be found to 

 traverse the strata in a slightly oblique direction. At all events, 

 judging from the ancient walls of the rock alone from whence the 

 ore has been extracted, I came to the conclusion that, although more 

 or less parallel to the highly inclined strata of mica schist, it must 

 be considered a true vein. In fact, besides crystals of calc spar, 

 hornblende, quartz and other minerals, films of earthy serpentine 

 and finely polished slickensides occur upon the walls of the parent 

 rock from whence the iron ore has been extracted (some of these 

 masses being charged with magnetic iron), thus leaving little doubt 

 that here, at all events, the metalliferous matter has resulted from 

 an action of an eruptive nature, which had penetrated the body of 

 the rock, chiefly indeed between its laminae of deposit, but long 

 after its original formation. In short, I completely agree with Baron 

 Berzelius, that however much some of the Swedish metalliferous 

 products may at first sight appear to lie in beds, they all belong to 

 true veins. 



2. Coast of Smoland, and Isles of Oland and Gothland. 



The large and fertile islands of Oland and Gothland, which lie 

 to the east of the province of Sweden, called Smoland, have long 

 been known to consist chiefly of ancient or transition limestones. 

 In a former memoir, as well as in the work on Russia, I have endea- 

 voured to show, that whilst Oland, lying near to the mainland, is 

 composed of sandstone, schist and Orthoceratite limestone (i. e. of 

 the same Lower Silurian strata known in other portions of Sweden), 

 Gothland, situated nearly in the middle of the Baltic Sea, is a true 

 Upper Silurian deposit. This conclusion was indeed arrived at 

 solely by the inspection of the fossils and the evidences given in the 



* So powerful is the magnetic attraction, that my compass was here carried 

 round 35° to the west. * 



