IN GLEN TILT. 



369 



ADDITIONAL NOTES. 



Note A, parag. 2. 



In tracing up the course of the Bruar, we made the following obser- 

 vations. 



About a hundred yards north from the road to Dalnacardoch, the 

 rock by the side of the river is mica-slate, stretching N. 36° E., and 

 dipping southeast at an angle of 37". Immediately above this, the 

 river, in its descent through a long succession of falls, crosses the stra- 

 ta, and displays a deep section of them at the bottom of a ravine. 

 The prevailing rock is mica-slate. 



At the first bridge in the walks made by the Duke of Atholl, there 

 is a bed of grey porphyry interposed between the strata of mica-slate. 

 Its chief ingredient is a brownish-white felspar, in crystals that are 

 crowded together, and not very distinct ; and these are imbedded in a 

 base of compact felspar, penetrated by mica and hornblende. Near 

 the second bridge, the mica-slate stretches N. 27° E., and dips 

 S. E. 39°. 



About a mile and a half from the road, and not far from the river, 

 there appears another bed of grey porphyry interposed between the 

 strata of mica-slate. The base of this porphyry seems to be compact 

 felspar, minutely penetrated by hornblende; and there are imperfect ' 

 crystals of hornblende interspersed. The stretch is here N. 47° E., 

 and the dip S. E. 53°. 



A quarter of a mile farther up, the rock is of mica-slate and gneiss, 

 stretching N. 16° E., and dipping to the eastward 23°. 



In proceeding by the side of the river, we saw mica-slate in several 

 places, to all appearance conformable, in its average dip and stretch, 

 with that last observed. 



About 



