144 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail. 8, 



Eeptilifcrous Sandstone) in the county of Sutherland are such as to 

 prove that these strata are of Secondary age, and that they are older 

 than the Lower Lias. 



I have argued this question hitherto mainly on stratigraphical 

 grounds, and have shown that there Avould be the strongest reasons 

 for believing the formation in question to be of Secondary age, even 

 if there were a total absence of all palseontological evidence. 



But this is very far from being the case. The interesting de- 

 scriptions of Stagonolepis, Telerp'eton, and Hyperodapedon by Pro- 

 fessor Huxley, and his discussion of their bearing on the age of 

 the Reptiliferous Sandstones of Elgin are too fresh in the minds of all 

 geologists to need recapitulation here. In 1858 Professor Huxley 

 declared* that the palaeontological evidence in favour of the Secon- 

 dary age of the reptiles was so weighty as to " lead one to require 

 the strongest stratigraphical proof before admitting the palaeozoic 

 age of the beds in which they occur." Since that date he has, as 

 every one is aware, greatly strengthened that palaeontological evidence 

 by demonstrating that, alike in Warwickshire, Devonshire, and India, 

 Hyperodapedon occurs in beds of Triassic agef. 



Thus we find that the stratigraphical and the palaeontological 

 evidence with regard to this interesting formation in the north-east 

 of Scotland are in complete accord, and we are justified in regarding 

 it as of undoubted Triassic age — a fact which is of the greater in- 

 terest from the circumstance that strata of that period are of such 

 rare occurrence in Scotland. 



Sir Roderick Hurchison has suggested that, if the Reptiliferous 

 Sandstones are to be referred to the Trias, they must in all proba- 

 bility be considered as representing the Keuper sandstones J. In 

 that case it may be consistent to place the " Cherty Rock of Stotfield " 

 on the horizon of the lower part of the New Red marls. The partial 

 break indicated by the overlying conglomerate beds, unattended as it 

 is by any difference of dip, would be perfectly consistent with the 

 absence of the higher portions of the Keuper series. 



It was also pointed out by Sir Roderick § that there might be in 

 Elginshire and Ross-shire an accidental conformity between beds dif- 

 fering as greatly in age as the Trias and Upper Old Red, and that 

 on this supposition the apparent anomalies presented by the district 

 might be accounted for. From a careful examination, however, of 

 the whole question of the relations of the Primary and Secondary 

 rocks around the Moray Firth, I am led to infer that the true key to 

 the enigma presented by the Elginshire rocks is to be found in the 

 great faults which certainly traverse the whole of the district, and 

 as certainly have been the cause of even more striking pbenomena 

 in other parts of it. 



There are good reasons for believing that these Triassic strata of 

 the north-east of Scotland are, like those of England (as has been 



* Quart. Journ. Geol. Soe. vol. xv. (1859) p. 460. 



t Ibid. vol. xxv. (1869) p. 138. 



t Siluria, 5th edit. (1867) pp. 267, 268. 



§ Ibid. 



