A DISCOVERY. 379 



that leans against the Hill of Nigg, I have succeeded in 

 making something approaching to a discovery. I have 

 described in my geological volume one great platform of 

 death in the Old Red, above which fossil remains are 

 very unfrequent. I discovered to-day in this section 

 that there are two platforms of death equally abundant 

 in organisms, the one three hundred and eighteen feet 

 above the other. Nor does any change seem to have 

 taken place in species in the long lapse that intervened, 

 as the fossils of the lower and upper platform seem 

 identical. I disinterred out of both specimens of 

 Coccosteus, Osteolepis, and Cheiracanthus, that could 

 not be distinguished with reference to their localities. 

 This discovery throws a good deal of additional light on 

 the geology of the district, and solves for me one or two 

 problems which lay unsolved before. I found besides, 

 under the northern Sutor, a recent deposit that belongs, 

 I am inclined to think, to the period when the sea stood 

 high over the floor of the pigeon cave. It is composed 

 of an adhesive blue clay, not very unlike some of the 

 rich blue clays of the Lias, but the remains which 

 it rather plentifully contains are all recent, bits of de- 

 cayed wood, among which I could distinguish pieces of 

 common fir and alder, the common mussel, and a not 

 very rare Venus, fir-cones, and hazel-nuts. I was a 

 good deal interested in this last discovery. We have 

 on the Cromarty side a considerable quantity of the 

 same blue clay, and until now I could never find aught 

 to determine its age by.' 



' Thursday morning. 



' Nothing like perseverance ! I have been out again 

 at the fish -beds, and have got some capital specimens. 

 It is truly wonderful how thickly the fish must have 



