the Primary Rocks and the Oolitic Series in the North of Scotland. 145 



on this part of the coast leads to the same conclusion ; for we find them with 

 mere local exceptions, which do not affect the rule, dipping- towards the central 

 line of tliis imaginary trough. Thus on the coasts of Sutherland and Ross 

 they generally dip towards the south-east, but on the shores of Nairn El^-in 

 and Banff, the prevailing- dip is north-west. 



As the whole line of coast is nearly parallel to the secondary deposits, it 

 follows that we can only become acquainted with their relations by examining 

 a number of transverse sections, commencing- with the primary mountains, and 

 ending with those points of the sea shore which exhibit the highest visible 

 parts of the series. To this observation there is, however, one very remark- 

 able exception. Two great masses of gneiss* penetrated in all directions by 

 veins of granite, appear to have been elevated after the deposit of the 

 whole secondary system ; and, at the time of their protrusion, not only to have 

 lifted up several beds of the lias formation, but to have produced a consider- 

 able derangement in the upper part of the red sandstone and conglomerate 

 seriesf- In consequence perhaps of this derangement, the beds between the 

 North Sutor of Cromarty and Tarbet Ness are seen with a northern dip^ and 

 inchned at a high angle; and a coast section of about fifteen miles in extent 

 conducts us, step by step, through a great succession of deposits, ending at 

 Tarbet Ness in the highest part of the series, which may be compared with 

 the upper red sandstone on the shores of the Pentland Firth. 



] . Transverse Sections of the Seco7idary System in Ross-shire, ^c. ^c. in 



ascending order. 



We before stated, that the conglomerate system was greatly expanded to 

 the south of the Dornoch Firth ; and as deep transverse gorges have been cut 

 through it by the Alness and the Alt-Grant rivers, which greatly favoured our 

 examination, we commence our first section with the old conglomerates which 

 appear in the higher part of those rivers resting upon the primary mountains. 



thousand feet high on the side of Mealfourvonie, or even into the lower elevations in the neigh- 

 bourhood of Foyers, without filling up a great portion of the valley of Loch Ness. Tiiis valley 

 must, therefore, have existed anterior to the secondary epoch, and must have been then choked up ; 

 and, in after times, it must have again been opened out by those operations (perhaps referrible to 

 many successive epochs) which have formed the greater denudations of our secondary strata, and 

 of which the lofty pyramidal mountains of stratified sandstone and conglomerate are among the 

 most imposing monuments. On this subject we refer to the descriptions of Dr. MacCulIoch. 

 (Geology of the Western Isles, vol. ii. pp. 90, 93, &c.) 



* See Geol. Trans, Second Series, vol. ii. Part II. p. 308—309. Part III. p. 353. 



t See Plate XIV. fig. 3. 

 VOL. III. SECOND SERIES. U 



