MII4ERALOGY OF THE OCHILS. 



Pitcaithly ^ and Dunning ; and to the westward of 

 the latter place. Its colour is a dark brick-red, 

 brownish red, and reddish grey. It is coarse- 

 grained, occasionally it becomes conglomerated, 

 as to the south of Dunning, where it rests on the 

 reddish-grey sandstone, and contains considerable 

 masses of quartz, fine-grained sandstone, and scales 

 of silver- white mica. This sandstone is occasion- 

 ally highly crystalline, bearing some resemblance 

 to iron-flint. When the mica predominates, it 

 assumes a slaty character, and decomposes into 

 tables. 



It occurs distinctly stratified, dipping to the 

 south-east, with an apparent direction from north- 

 east to south-west. I have not seen it in con- 

 nexion with any other rock, except below the 

 Humbling Bridge in the course of the Devon, 

 where it alternates with a tuff ; and at the foot of 

 the King's Seat, near to the house of Harviestonf, 

 where it rests immediately above a seam of slaty 

 pitch- coal, six feet two inches thick. From the 

 resemblance of its characters to those of another 

 sandstone to be hereafter noticed, it is highly pro- 

 bable, that they will be found to belong to the 

 same formation ; bpt as they have not been traced 

 in distinct connexion, it maybe well to keep them 



* This is a small village in Perthshire, celebrated for a mi- 

 neral spring, to which considerable efficacy has been ascribed, 

 t The seat of my friend Craufurd Tait, Esq. 



