RAMBLES OF A GEOLOGIST. 325 



CHAPTEK VII. 



THE ravine excavated by the mill-dam showed me what I 

 had never so well seen before, the exact relation borne by 

 the deep red stone of the Cromarty quarries to the ichthyo- 

 lite beds of the system. It occupies the same place, and be- 

 longs to the same period, as those superior beds of the Lower 

 Old Red Sandstone which are so largely developed in the cliffs 

 of Dunnet Head in Caithness, and of Tarbet Ness in Ross- 

 shire, and which were at one time regarded as forming, north 

 of the Grampians, the analogue of the New Red Sandstone. 

 I paced it across the strata this morning, in the line of the 

 ravine, and found its thickness over the upper fish-beds, though 

 I was far from reaching its superior layers, which are buried 

 here in the sea, to be rather more than five hundred feet 

 The fossiliferous beds occur a few hundred yards below the 

 dwelling-house of Rose Farm. They are not quite uncovered 

 in the ravine ; but we find their places indicated by heaps of 

 gray argillaceous shale, mingled with their characteristic ich- 

 thyolitic nodules, in one of which I found a small specimen 

 of Cheiracanthus. The projecting edge of some fossil-charged 

 bed had been struck, mayhap, by an iceberg, and dashed into 

 ruins, just as the subsiding land had brought the spot within 

 reach of the attritive ice ; and the broken heap thus detached 

 had been shortly afterwards covered up, without mixture of 



