Geology of the Harz Mountains. 207 



contains from 85 to 600 oz. of silver per ton of ore. Two 

 small lumps of native gold were found in the quartz as it 

 was being crushed under the hammer. 



The veins unfortunately become barren as they pass down 

 into the schists below the calcareous zone, and at a depth of 100 

 feet below the surface they were found to consist of white 

 quartz alone, thus rendering all further working unproductive. 



V. — Ardtalnaig. 



Small veins of galena and blende have been exposed by 

 costeaniug on the side of the hill E. of Ardtalnaig, — a village 

 on the south side of Loch Tay, about a mile N.E. of Tomna- 

 dashan, but they are far too thin to give any hope of future 

 productiveness. The principal vein has been opened out at 

 a spot on the hillside about 900 feet high, and due E, of 

 Ardtalnaig where the schists are traversed by a sheet of 

 intrusive felsite of pale cream colour and perfectly compact 

 texture. The vein runs through the felsite, into the mica 

 schist, and then passes again into the intrusive rock. It is 

 interesting to note that where it is in the schist, galena and 

 blende are both present, in a matrix of barytes and quartz, 

 while the portions of the vein traversing the felsite contain 

 galena and quartz but no blende. 



Many other small threads and strings of ore intersect the 

 schists around Kenmore and along the shores of Loch Tay. 

 but none have been discovered with any approach to work- 

 able thickness. 



XVII I. The Harz Mountains : their Geological Structure and 

 History. By Henry Moubray Cadell, Esq., B.Sc, 

 Edin., H.M. Geological Survey of Scotland. [Plates 

 IX. and X.] 



(Read 16th January and 20th February 1884.) 



Contents. 



I. INTRODUCTION^. 



II. topography of the harz. 



III. GEOGNOSY OF THE HARZ. 



1. Arch^an Rocks of the Kyffhauser Range. 



2. Older Paleozoic Core of the Harz (Kerngebirge). 



a. Hercynian ; h. Devonian ; c. Culm. 



