580 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



proved, such correct views on the geology of so wide a range of coun-^ 

 try. In giving my adhesion to the views of Sir Eoderick Murchison 

 in preference to those of Professor Nicol regarding the age and the 

 true geological position of the various rocks of this district, I beg 

 leave distinctly to state that I found the facts and observations of 

 Professor Nicol regarding the mineralogy and arrangement in situ of 

 the various rocks so accurate and complete as to leave nothing 

 further to be desired in that respect. I beg leave further to say, 

 that I believe, had Hugh Miller lived to see the fauna of Silurian 

 fossils discovered by Mr. Peach in the Duimess limestones, he would 

 have changed his views in accordance Avith the additional evidence 

 thus given upon the points in dispute. I have merely to add that I 

 went over the ground twice in order to verify my observations, and 

 that I shall commence my short descriptions of the various forma- 

 tions with the gneiss of Cape Wrath, and proceed eastward in the 

 ascending order until we arrive at Duncansby Head, on the north- 

 east comer of Scotland. 



Gneiss of CapeWrath. — CapeWrath proper, forming the north-west 

 angle of Scotland, and on which the lighthouse stands, is composed 

 of gneiss intersected by veins of granite ; it dips to the south-east at 

 a high angle, and immediately east of, and beside the lighthouse, the 

 dip is almost vertical, with the edges of the upturned strata exposed 

 towards the north in the face of the perpendicular chifs to the 

 height of 400 feet. Close beside the road, about a quarter of a mile 

 from the lighthouse, there is a small patch of conglomerate resting 

 unconformably upon the edges of the gneiss. The gneiss continues 

 eastward along the sea-shore to Clashcarnoch Bay*. This httle bay, 

 about a hundred yards in width, seems to have been formed by the 

 continued action of the waves along the hne of a fault in the face of 

 the perpendicular chif, and forms the very picture of sterility and 

 desolation ; it is the only landing-place in the vicinity, and the 

 Lighthouse Commissioners have erected a boat-slip there for landing 

 stores for the lighthouse. The dip of the gneiss is here almost ver- 

 tical, inclining however to the south-east. Prom Clashcarnoch Bay 

 it is then prolonged on the sea-shore to Kers\dck Bay, about three 

 miles from Cape Wrath, at an altitude of from 300 to 400 feet above 

 the level of the sea ; and at the west side of Kerwick Bay it suddenly 

 sinks into the sand, and is succeeded by the sandstone of CapeWrath 

 as it is generally termed. 



Sandstone of Cajpe Wrath. — On the east side of Kerwick Bay the 

 purple sandstones and conglomerates rise into a perpendicular cliif 

 to the height of from 400 to 500 feet above the level of the sea. 

 Immediately at the foot of this cliff seaward is the detached and 

 picturesque rock of " Stack o Chlo," with its horizontal lines of 

 stratification corresponding exactly with those of the adjoining main- 

 land. From Kerwick Bay the sandstone extends eastward for four 

 or five miles along the sea-shore, and it is well seen along the road 

 for the same distance. It extends southward for twelve miles to the 

 rivulet of Achriesgill, within two miles of Rhiconich Inn, and within 



* At Clashcarnoch Bay the massive solidity and mineralogical peculiarities of 

 the gneiss of Cape Wratla can be seen to great adrantage. 



