170 MINERALOGICAL ACCOUNT 



is first a bed of compact-felspar ; over it breccia, 

 with layers of a rock of felspar, inclining to clay- 

 stone and much intermixed with quartz ; and above 

 all, beds of amygdaloid. At Bordie, there are 

 first vertical strata of felspar, separated from 

 each other by thin layers of greenish clay. The 

 felspar is in the form of globular distinct con- 

 cretions, with cavities lined with quartz, or fil- 

 led with steatite : this bed is covered with beds 

 of breccia, similar to those at Little-Peatie's-gio, 

 in an unconformable position, the strata of felspar 

 being vertical, and those of the breccia horizon- 

 tal. The strata of breccia are separated by clay, 

 similar to that which separates the strata of fel- 

 spar. A bed of red compact felspar covers the 

 breccia. The breccia, in this place likewise, 

 contained fragments of sandstone. 



COMPACT-FELSPAR. 



This rock is of a reddish-brown colour, and 

 occurs in the form of thick beds, which, in some 

 instances, appear to be seamed or stratified. At 

 Lammer-banks, on the east side of Houseavoe, it 

 rests on beds of sandstone, being separated there- 

 from by a thin partition of clay. Both these beds 

 rest in a horizontal position. The compact-fel- 

 spar is porphyritic, containing crystals of felspar, 

 likewise of a red colour. This bed, in another 

 place between the Kirk-sand and Forewick, alter- 

 nates or rather is intimately mixed with a variety 



