the PrimarT/ Rocks and the Oolitic Series in the North of Scotland. 129 



serving- the same relations it ranges into the denudation of the Beauley river, 

 — and that it follows the sinuosities of the valley, and ascends towards the 

 west several miles beyond the boundary line, which is indicated by its position 

 on the neighbouring- hills. 



On the south shore of Loch Beauly the conglomerates are contracted into 

 a narrow zone, and for a short space are entirely cut off. They then resume 

 their range, and occupy the whole extremity of the projecting ridge which 

 comes down to the coast near Inverness, between the Beauly Loch and the 

 valley of the great canal ; appearing in their most characteristic form, like 

 great independent protuberances embossed upon the sides of the mountains. 

 From Inverness they ascend far up the ancient transverse valley of the High- 

 lands. Near the north-eastern extremity of Loch Ness they are interrupted 

 by projecting masses of granite and of gneiss, beyond which they again set 

 on ; and to the west of Glen Urquhart they compose a mountain range, and 

 reach the summit of Meal-Fourvonie, from which they gradually descend to 

 a lower elevation, and are continued to the neighbourhood of Fort Augustus. 

 Their range and general appearance on the south-east side of Loch Ness have 

 been too often described to require any additional notice : we may however 

 remark (on the authority of Mr. Anderson of Inverness), that although 

 interrupted by a hill of gneiss on the west side of Foyers, they afterwards 

 range by the side of the loch at a lower level ; and that they have also been 

 traced along the shores of Loch Oich. All the northern portions of the 

 counties of Nairn, Elgin, and Banff, present a dull outline, and are of com- 

 paratively low elevation ; but in these districts the old conglomerates are occa- 

 sionally laid bare, and are represented, though in an obscure and degraded 

 form, by the lower beds on the Findhorn and on the Spey, — by the conglo- 

 merates on the hills to the south of Forhabres, — and by the detached rocks in 

 the bay of Cullen. At the promontory of Cullen the whole system is cut off 

 by the line of coast ; but, at Troup Head, a conglomerate rock reappears, 

 ae-reeino- in its £:eneral character with the masses which we have been at- 

 tempting to describe *. 



The preceding sketch may serve to convey a general notion of the range 

 of the old conglomerate through Caithness and along the Murray Firth, and 

 of its relations to the more ancient rocks of the neighbouring districts. 



General Structure of Caithness. 

 The external form of the county approaches to that of a triangle, the two 

 sides of which are washed by the North Sea and the Pentland Firth. The 



* See Geol. Trans. Second Series, vol. ii. Part III. p. 3G3. 

 VOL. III. SECOND SERIES. S 



