HARRIS. MINERALS. ] 65 



and is often accompanied by a sort of micaceous schist, 

 the position being irregular, but generally vertical. 

 It is of a character very strongly resembling one of the 

 varieties found in Tirey; being of a pale or dark grey colour 

 speckled with darker spots of the same, and sometimes 

 even verging to a blue ; more rarely greenish, and 

 containing specks or large pieces of transparent serpen- 

 tine. At times it contains grey and watery sahlite or 

 dark green coccolite, either dispersed in grains v or inti- 

 mately blended with the general mass, or lastly aggre- 

 gated into lumps : it also contains mica disposed in a 

 similar manner. Hornblende also occurs in it as in 

 that of Tirey, in large concretions, but is more rare 

 than the sahlite. On the shore at Rowdill, and in various 

 other places, green compact felspar is found, forming an 

 integrant portion of the gneiss, and often in very large 

 masses. This substance is very prevalent throughout 

 these islands, as it is in Tirey, Coll, and lona. 



But among the simple minerals to be seen in Harris, 

 felspar, as might be expected, is the most conspicuous. 

 It forms distinct concretions in the gneiss, often of very 

 large dimensions, and appears under a great variety of 

 aspects. It occurs in very large masses of a pearly 

 lustre, and semi-transparent, accompanying the graphic 

 granite before mentioned, and forming specimens of 

 great beauty. From this it is found gradually tending 

 to the more common foliated variety, and at length ap- 

 proaching to the aspect of the compact kind, while its 

 colour passes through various stages of ochre-yellow to a 

 deep flesh colour. On that side of Roneval which faces 

 Rowdill there is a vein of quartz of a rare variety and 

 of great beauty. It is chiefly granular, emulating the 



certain allusions in oriental worship, objects of much curiosity. They 

 are hence unfit for notice in a work of this nature. Any remarks 

 would moreover be superfluous, as they will probably in no long time 

 receive illustration from a pen to which the public has lately beet* 

 indebted for a great part of its amusement. 



