148 Rev. A. Sedgwick and Mr. Murchison on Deposits contained between 



measures. In general, however, a red tinge is more prevalent in the rocks 

 we are describing-, than in the ordinary gritstone of the carboniferous strata; 

 and the more coarse and rubbly beds associated with them, as well as the sub- 

 ordinate strata of flagstone and micaceous slate clay, are almost universally 

 red or variegated. The same observations may be applied to most of the 

 varieties of sandstone which are extensively quarried on the north shores of 

 the Beauly Loch in the Ulack Tsle, and in many other parts of Easter Ross. 



This second range of conglomerate mountains gradually declines in eleva- 

 tion towards the south-western angle of the Cromarty Firth, but is prolonged, 

 if we mistake not, into the hills above Brahan Castle; and the same part of 

 the system is probably represented by the great masses of conglomerate which 

 form the hills on the north side of the Beauly Loch, immediately opposite 

 Inverness*. 



So far there appears a very strict analogy between the conglomerate system 

 of Caithness (especially as it is laid down in the eastern coast section), and 

 the successive deposits which we have last described ; the mineralogical dis- 

 tinctions arising naturally from the different characters of the primary rocks, 

 out of the degradation of which tlie secondary formations have arisen. But 

 in leaving the conglomerate mountains, and descending to the lower regions 

 of Easter Ross, we lose all distinct traces of this analogy ; and the whole sub- 

 soil (not only in the low region bordering on the north shore of the Cromarty 

 Firth, but also in the greater part of the Black Isle), appears to be composed 

 of sandstone having the general charartors already described. The district 

 is much covered by accumulations of turf-bog, and of alluvial matter; so that 

 we should find it difficult to determine whether any other beds were subordi- 

 nate to the sandstone, had not the two Sutors of Cromarty produced an inver- 

 sion of dip and a great derangement, by which a considerable succession of 

 beds is exposed in fine open coast sections. In the low region before alluded 

 to, the dip is inconsiderable, but on the whole tends to the south-east. Taking 

 the line of section towards the North Sutor, the dip becomes inverted ; and 

 before reaching the protruding gneiss, the sandstone beds are nearly vertical f. 



* The structure of the country near Inverness appears to be strictly analogous to that which 

 is described in the text. The primary rocks are immediately succeeded by conglomerate. To 

 the north-west of the town, the bituminous schist (like that in the higher part of Alt-Grant) 

 does not appear : but it does appear (as above stated) to the south-east ; and a portion of it may 

 perhaps be buried under the Murray Firth. At all events, beds of sandstone like those which 

 are associated with the bituminous schist are quarried on the north shores of the Loch, and these 

 are surmounted by the conglomerates of the Black Isle, which, in this view of the subject, must 

 represent the inner zone of the Ross-shire conglomerate. 



t See Plate XIV. fig. 3. 



