194 Proceedings of the Boyal Physical Society. 



joint vein was found to contain very little ore of any value. 

 This fact is of importance in its bearing on the future of the 

 mineral workings at Tyndrum. The southern slope of the 

 mine hill lies below the line of junction, and carries the crop 

 of the united veins, so that in this direction a decrease in the 

 quality of the ore can only be expected. So far as our 

 observations go, this is the case, for an examination of the 

 vein where it crosses the Allt nan Sae soon showed it to be 

 very poor in metalliferous minerals, and indeed to be hardly 

 deserving of the designation " metalliferous " vein at all. 

 Some good ore has, however, been found in a costean at the 

 place where the vein crosses the Coninish Water about 

 three-quarters of a mile S.W. of the Allt nan Sae section. 



The hard vein is intersected and dislocated by two cross 

 courses which terminate in the west wall of the clay vein, 

 while the united vein in the lower workings is dislocated by 

 a third cross course. These minor cross faults have produced 

 no important deviation in the trend of the hard vein which 

 runs continuously northwards from the mine, maintaining its 

 general bearing of N. 35° to 40° K, and has been traced to 

 the top of Beinn a Chaisteil, 4 miles from Tyndrum. 



l. Mining at Coninish has been carried on by two sets of 

 openings at different parts of the vein. The most easterly 

 of the workings are in the deep corrie in the side of Beinn 

 Chuirn above Coninish. The vein, which is here several 

 feet thick, runs up the rugged precipitous side of the corrie, 

 where some of the old stopes can be seen as well as the 

 mouths of the levels driven into the hill along its course. 

 In the main or Beinn Chuirn level the vein consists of about 

 1 foot of good ore with white quartz on each side, above 

 which the hard quartzite forms a strong hanging wall. The 

 levels communicate with the surface by a shaft driven 470 

 feet upwards to the top of the cliff. The mines were aban- 

 doned about thirty years ago, and during that period so much 

 mud and peaty matter has been washed down through the 

 opening that the main level is nearly impassable a short 

 distance inwards from its mouth. The other working known 

 as the Beinn Lui ^ Level was on the Allt an Lund, 1 mile 



^ Erroneously spelt Beinn Laoigh on the Ordnance Map. 



