1862.] HAKKNESS METAMORPHIC ROCKS. 339 



exposed in its course, seems to flow altogether over quartz-rocks 

 dipping S.E., with granite in them, and these form Den Duan. 

 "West from Kildonnan, granite becomes more abundant, and at 

 Kinbrae it forms the rock of the country. 



The district north of the Scarabins, for the most part, consists of 

 members of the Old Red series. In the Berridale River they are 

 seen associated with, and in some instances made up of, granite- 

 fragments. Mr. Peach, who has examined in considerable detail 

 the rocks traversed by this river, and who has furnished Sir 

 Roderick Murchison with notes of his observations, which Sir 

 Roderick has forwarded to me, finds in the course of this stream 

 localities where white quartz-rocks, evidently an extension north- 

 wards of those of the Scarabins, " dip to the south at an angle 

 of 50°." 



In the bed of the same stream, Mr. Peach remarks that above the 

 bridge of Dalsea ^' gneiss occurs, which soon becomes twisted and 

 contorted in all directions, and penetrated by granite -veins. Higher 

 up the stream it is less contorted, but vertical, the granite being 

 very coarse, and enclosing large masses of talc, called here ' Sheep's 

 silver,' and giving the name of ' Silver-rock ' to this part. The 

 gneiss may be traced to above the bridge of Corrachoich, where it is 

 very full of mica, and breaks into flakes like micaceous schist, and 

 it dips to the south at an angle of 60°. On it rests a small band of 

 hard white quartz, like that of the Scarabins." Mr. Peach's notes 

 also contain an account of the Old Red series, as this is seen in the 

 Berridale section. 



Westward from the Scarabins to Achintoul, the country, which is 

 principally composed of granite, is for the most part moory, and 

 affords no good sections. 



In traversing the country in a N.W. direction from Achintoul to 

 Strath Naver, the nature and the arrangement of the rocks which 

 occur in this portion of Sutherland can be recognized. In the river, 

 immediately west from Achintoul, gneiss is seen with a S.E. inclina- 

 tion ; and in the flat moory country on the west side of the river, 

 granite-bosses appear abundantly at intervals at the surface. In 

 the course of the Alt-doura-damff, which flows from the N.W., 

 granite and gneiss occur, the latter dipping also S.E. 



Eollowing up the course of this stream between Ben-griam-more 

 and Ben-griam-beg (two mountains of Old Red Conglomerate, laid 

 down in Sir Roderick Murchison's map), the country becomes boggy, 

 and no exposures of rock are seen. At Loch Leune-a-chliaven, on 

 the west side, granite and gneiss again occur, the latter having like- 

 wise the S.E. dip ; and, like aU the gneiss of Sutherland which is 

 much associated with granite, it is of a very crystalline nature. 

 Granite and gneiss are also seen at Loch Ganieu of a like character, 

 the gneiss having the same S.E. inclination ; and N.W. from this, at 

 Coul-loch-more and Coul-loch-beg, the same rocks appear*. 



^ About a mile south of Coul-loch-beg, beyond a moorj, swampy tract of 

 country, occurs Ben Vaddu. The form of this hill differs altogether from those 

 which are made up of granite and gneiss in Sutherland, and has a great resem- 



VOL. XVIII. PART I. 2 A 



