the Primary/ Rocks and the Oolitic Series in the North of Scotland. 137 



stone are extensively quarried at various places in this hilly tract; and one of 

 the finest specimens of the characteristic fossil fish was found in a thick 

 calcareous flag- bed N.W. of Lybster. 



Ben-na-Cheilt is the hig-hest point of this reg-ion, and is seen from all parts 

 of the northern and western plains. The strata are arranged in a fan-shaped 

 form around this hill ; so that the same beds which atNottinghan and Latheron 

 Kirk, near the coast, dip westerly, at Braelungie, five miles inland, have veered 

 round and dip to N.E. ; and still further in the interior, at Ach-na-Vainish 

 inn, the dip is brought round to E.S.E. With this great change in their lines 

 of bearing, the beds, from being nearly horizontal on the coast near Latheron, 

 increase in their angle of inclination so much, that at Ach-na-Vainish they dip 

 from 30° to 40°. This lower part of the slaty series differs from the upper 

 chiefly, in being more thick-bedded and siliceous. At Latheron Wheel on the 

 coast, the beds are nearly horizontal ; but they rise between that place and 

 Dunbeath into micaceous sandstones, alternating with blue calcareous fla<'- 

 stones : and, as the latter are here abundantly charged with fossil fish of the 

 very same species which are found in the highest part of the system, it is 

 evident that the whole schistose series of which the greatest part of Caithness 

 is composed, must be referred to one great and protracted epoch. 



At Dunbeath, the beds consist of bluish and grey, close-grained sandstone, 

 having a tendency to exfoliate parallel to the laminae of deposit, which are 

 highly micaceous. These alternate with certain greenish and bluish coloured 

 flagstones, and are prolonged high into the hills until they distinctly repose 

 upon, and graduate into, the old red conglomerate of Uraenjore, which is con- 

 nected with the chain of the Maiden Paps. On the coast, the same slaty beds 

 extend considerably to the south of Berridale, with the exception of an in- 

 truding mass of the old conglomerate at Borgue Head, where its presence is 

 probably owing to the degradation of the nearest points of the primary rocks 

 of the Scarabin Hills. This isolated mass of conglomerate is nearly vertical, 

 and disintegrates into irregular prismatic forms ; and the flagstone in the cliff 

 on both sides, dips away from it at a rapid angle to the S. W. and S.E. ; but at 

 a little distance from it, it recovers its average inclination. All these lower 

 slaty beds exhibit the same forms as those of the higher parts of the series, in 

 their mode of disintegration, and in having the same vertical gulleys or inden- 

 tations, the sides of which are frequently of a red colour on the exterior, but 

 of a greyish blue when freshly fractured. 



Coast Section of the Old Red Conglomerate of Caithness, dgc. 

 The general range of this deposit, and its enormous development in (he 



VOL. in. SECOND SERIES. T 



