On the Geological Structure of the North of Scotland. 73 



division of the Old Red Sandstone of Caithness and the Orkney- 

 Islands, the author showed how the chief member of the group in 

 those tracts diminished in its range southwards into Ross-shire, and 

 how, when traceable through Inverness and Nairn, it was scarcely 

 to be recognized in INIorayshire, but reappeared with its characteristic 

 ichthyolites in Banffshire (Dipple, Tynet, and Gamrie). 



He then prefaced his description of the ascending order of the 

 strata belonging to this group in iNIorayshire by a sketch of the suc- 

 cessive labours of geologists in that district ; pointing out how in 1 828 

 the sandstones and cornstones of this tract had been shown by Pro- 

 fessor Sedgwick and himself to constitute, together with the inferior 

 Red Sandstone and Conglomerate, one natural geological assemblage; 

 that in 1839 the late Dr. Malcomeson made the important additional 

 discovery of fossil fishes, in conjunction with Lady Gordon Camming, 

 and also read a valuable memoir on the structure of the tract, before 

 the Geological Society, of which, to his, the author's regret, an abs- 

 tract only had been published. (Proc. Geol. Soc. vol. iii. p. 141.) 



Sir Roderick revisited the district in the autumn of 1840, and made 

 sections in the environs of Forres and Elgin. Subsequently Mr. P. 

 Duff, of Elgin, published a ' Sketch of the Geology of Moray,' with 

 illustrative plates of fossil fishes, sections, and a geological map by 

 Mr. John Martin ; and afterwards Mr. Alexander Robertson threw 

 much light upon the structure of the district, particularly as regarded 

 deposits younger than those under consideration. 



All these writers, as well as Sedgwick and himself, had grouped 

 the yellov,' iind whitish yellow sandstones of Elgin with the Old Red 

 Sandstone ; but the discovery in them of the curious small reptile, the 

 Telerpeton Elginense, described byMantell in 1851, from a specimen 

 in Mr. P. Duff's collection, first occasioned doubts to arise respect- 

 ing the age of the deposit. Still the sections by Capt. Brickenden, 

 who sent that reptile up to London, proved that it had been found 

 in a sandstone which dipped under ' Cornstone,' and which passed 

 downwards into the Old Red series. Capt. Brickenden also sent to 

 London natural impressions of the foot-prints of an apparently rep- 

 tilian animal in a slab of similar sandstone, from the coast-ridge 

 extending from Burgh Head to Lossiemouth (Cummingstone). 



Although adhering to his original view respecting the age of the 

 sandstones, Sir R, Murchison could not avoid having misgivings and 

 doubts, in common with many geologists, on account of the high 

 grade of reptile to which the Telerpeton belonged ; and hence he 

 revisited the tract, examining the critical points, in company with 

 his friend the Rev. G. Gordon, to whose zealous labours he owned 

 himself to be greatly indebted. 



In looking through the collections in the public museum of Elgin 

 and of Mr. P. Duff, he was much struck with the appearance of 

 several undescribed fossils, apparently belonging to Reptiles, which 

 by the li])erality of their possessors, were, at his request, sent up for 

 inspection to the Museum of Practical Geology. He was also much 

 astonished at the state of preservation of a large bone (Ischium), 



