The Breadalhane Mines. 193 



occasional partings of mica schist, thus resembling in every 

 respect those of the Allt nan Sae. 



The mica schists are exposed in a continuously descending 

 section to the north of Clifton. The position of the fault at 

 this locality has been fixed by means of a " costean " made 

 by the Scots Mining Company at the east side of the Inver- 

 oran Eoad, and about | of a mile from the village. 



2. Geometrical Relations of {a) the Tyndrum and (&) 

 the Coninish Veins. — a. The metalliferous deposits at Tyn- 

 drum are all in veins, one of which is situated at Coninish 

 in the S. W. corner of the accompanying map, and the remain- 

 ing two in the more immediate neighbourhood of Tyndrum. 

 Other small veins are shown on the map, but we do not pro- 

 pose to describe them here, as we believe them to be of no 

 great commercial, or scientific interest. 



The Tyndrum veins run, as we have already seen, through 

 the Sron nan Colan, and the ore has been worked by means of 

 a series of levels driven into the northern side of the hill (Fig. 

 3). The Tyndrum " hard vein " is in the quartzites alongside 

 of the fault, and trends K 35° E., while the " soft " or " clay 

 vein " is generally in the fault fissure itself, which runs N. 

 40° E. This difference in direction makes the two veins 

 converge to a point at the top of the hill above the mines. 

 The resulting conjoint vein following the line of fault is 

 known as the " Tyndrum Main Vein," and runs south-west- 

 wards over the southern slopes of the Sron nan Colan, across 

 the Allt nan Sae, to the junction of the Allt eas Anie and 

 the Coninish Water at Coninish, whence it passes out of the 

 confines of the map. 



Working plans of the mine show both veins to hade to 

 east (Eig. 2), the hard vein at an angle of 65° to 70°, and 

 the clay vein at 80°. This difference in hade must bring 

 both veins together at a certain depth below the surface, and 

 the junction has actually been reached at the end of the 

 " New Level " shown in Eig. 3. Erom this point the line of 

 junction rises diagonally upwards, and, as we have already 

 seen, reaches the surface on the southern side of the crest of 

 the ridge. All the richest workings were in the hard vein 

 above this line, and, contrary to general experience, the con- 



VOL. VIII. N 



