J0K1ELY-— MINES OF N.W. BOHEMIA. 15 



characteristic of the sand of Alzey (Chenopus speciosus, Pleurotoma, 

 &c.) and of the Cyrena-marls prove the close connexion between these 

 formations. Respecting other tertiary formations, particularly those 

 of Baden, I hope soon to make some further communications. 



[W. J. H.] 



On the Metals and Mines q/ North-western Bohemia. 



By M. JOKELY. 



[Proceed. Imp. Geol. Instit. Vienna, April 1, 1856.] 



This communication comprises a general survey of the metallic pro- 

 ducts and mining operations in the Bohemian portion of the Erzge- 

 birge, the Fichtelgebirge, the Kaiserwald, and the northern extremity 

 of the Bohmerwald. The metals occurring in this district are silver, 

 uranium, nickel, bismuth, cobalt, lead, zinc, copper, iron, manganese, 

 and tin. The ores of this last metal, geologically speaking the most 

 important of the whole, are intimately and, it seems, necessarily con- 

 nected with granite ; as, when they occur in crystalline rocks, they 

 are only abundant where those rocks come in contact with granite. 

 The tin-mines in the district in question were in existence as early as 

 the twelfth and thirteenth centuries, and attained their full develop- 

 ment in the sixteenth century. Subsequent wars and calamities 

 caused their gradual decay, so that at the present time the workings 

 are confined to five localities. Two systems may be distinctly traced 

 among the stanniferous veins ; as one of them crosses the other they 

 are consequently of different age. 



Silver, nickel, bismuth, cobalt, and uranium are now the most 

 important objects of mining-industry within the district in question, 

 the centre of which is at Joachimsthal. At this place mines hare 

 been open ever since the beginning of the sixteenth century, and still 

 promise a long and prosperous exploitation * . 



The veins of ores of the above-mentioned metals, which are con- 

 tained both in mica-schist and in primitive clay-slates, extend into 

 the neighbouring mountains of Saxony. They may also be divided 

 into two groups ; the one running from south to north ; the other 

 from west to east, and cutting across those of the former group. 

 About a hundred and fifty of these veins have been opened for 

 exploitation within the mining-district of Joachimsthal. 



The argentiferous veins are but of subordinate importance in the 

 slates to the west of the Eibenstock-Neudeck granites. Lead- and 

 copper-ores, formerly worked on a large scale, are more developed in 

 the primary clay-slate of this locality : the exploitation of lead is now 

 confined to the Bleistadt-Priinlass district. The veins run from south 

 to north and from west to east, and are contained in mica-schist near 

 its line of contact with clay -slate ; they contain galena, iron-pyrites, 

 sulphide of zinc, and brown phosphate and white carbonate of lead ; 

 green phosphate of lead was formerly found in them. Some other 

 lead-mines are also worked in mica-schist. Those in clay-slates are 

 insignificant, on account of the poverty of their ores, Beds of sul- 

 * See Quart. Jotirn. Geol. Soc. vol. xii. part 2. Miscell, p. 6. 



