336 PEOCEEDIKGS or THE GEOLOGICAL SOCIETY. [May 21, 



stones is by no means constant, and the higher portions of the 

 metamorphic rocks of Banifshire present themselves in the condition 

 of gneiss, with associated quartzose layers, or, when only in a par- 

 tially altered condition, as greywacke-sandstone, with pebble-beds, 

 succeeded by greywacke-shales. 



There is one feature with reference to the metamorphic rocks of 

 this county which, although not confined to this district, but pre- 

 valent to a great extent in the whole of the metamorphic rocks of 

 Scotland, is of considerable interest. This is the great predominance 

 of S.E. dips. On referring to the map attached to Mr. Cunning- 

 ham's memoir, it will be seen that the strike of these metamorphic 

 rocks is extremely uniform, and that S.E. dips almost exclusively 

 obtain among the metamorphic series. 



An occurrence of this kind could only result from the planes of the 

 several axes being depressed towards the !N^.W., and by this circum- 

 stance producing, over a considerable area to the north-west of these 

 axes, an inversion of the strata, and so packing these together that 

 in many cases the superior deposits seem to occupy a position below 

 the lowest member of the series, the quartz-rocks. 



There is also another circumstance of interest in connexion with 

 the rocks of Banffshire, and which, like that just referred to, is 

 common likewise to other areas in the North of Scotland. This 

 is the shght influence which the plutonic rocks exercise in producing 

 the direction of the axes, or in modifying the inclination of the strata. 



The districts in this country which exhibit granitic or syenitic 

 masses have, on the flanks of these plutonic areas, the strata striking 

 right into them, and there is nothing like an indication of a peri- 

 clinal arrangement of altered sedimentary rocks around plutonic 

 masses. The small effect resulting from the influence of rocks of 

 this nature has been expatiated upon by Mr. Cunningham ; and he 

 gives many instances of the comparatively small part which they 

 have played in effecting the changes of position in, and in altering 

 the character of, the sedimentary rocks. 



§ 2. Section from the Sea at Berridale over the Scarabins to 

 Strath Naver. (Fig. 2.) 



There occurs, near the southern extremity of Caithness and on 

 the eastern side of Sutherland, a very extensively developed series of 

 quartz-rocks, and these form the hills which are known under the 

 name of the Scarabins. Their mineral nature is alluded to by Sir 

 Roderick Murchison and Professor Sedgwick, in their memoir " On 

 the deposits contained between the Primary Rocks and the Oolitic 

 Series in the North of Scotland"*, and they are also referred to by 

 the former in one of his memoirs on the Northern Highlandsf. 



Last summer, after examining the metamorphic rocks of Banff- 

 shire, I had an opportunity of traversing the Scarabins, and the 

 portion of Sutherland which lies between them and Strath Naver. 



* Trans. Geol. Soc, 2nd ser. vol. iii. p. 125 et seq. 

 t Quart. Journ. Geol. Soc, vol. xv, p. 384 ef seq. 



