President's Address, 393 



while a modioliform shell, like Modiola Macadami, one of the 

 commonest fossils of the Calciferous Sandstones of Fife and 

 Liddesdale, was also found to occur. This outlier may now 

 be looked upon with confidence as belonging to the Carboni- 

 ferous formation, and is thus the second patch noted north 

 of the Grampians, the other being that discovered by Pro- 

 fessor Judd on the shores of the Sound of Mull in 1877.i 



Before the time under consideration, the controversy regard- 

 ing the horizon of the Eeptiliferous Sandstones of Elgin had 

 already been practically ended in favour of their Triassic age 

 through the researches of Huxley and others. The discovery 

 in them of the Dicynodont remains and those of the other 

 Anomodontia described by E. T. Newton, in his Memoir pub- 

 lished by the Eoyal Society, strongly confirms this view.^ 



Prior to the time that the Geological Survey commenced 

 its operations in Arran, the red sandstones near the Cock of 

 Arran had been conclusively proved, by the late James 

 Thomson, to be newer than the Carboniferous Limestone. 

 He showed that fossils of that age were contained in the 

 derivative limestone boulders which make up their basement 

 conglomerates, but this evidence only led him to the con- 

 clusion that the newer rocks probably belonged to the Mill- 

 stone Grit. The work of the Geological Survey carried on 

 by Mr Gunn proved that the Eed Sandstones and conglomer- 

 ates south of the Cock of Arran rest unconformably on the 

 Coal-Measures, proved by their plant remains as above stated, 

 affording a strong presumption that they are either of Permian 

 or Triassic age. Similar evidence of the unconformability 

 of the Eed Sandstones to the Coal-Measures was found to 

 exist near Corrie and Brodick, and also near the head of 

 the Benlister Burn and Sliddery Water in the south of the 

 island. Although no direct fossil evidence was obtained 

 from the red sandstones beyond some indeterminable Plant 

 remains, Mr Gunn inferred that the rocks are of Triassic 

 age ; the red sandstones and conglomerates at the base repre- 

 senting the Bunter, and the overlying red marls and yellowish 



1 Quart Jour. Geol. Soc, vol. xxxiv. p. 685. 



^ Phil. Trans., vol. clxxxiv, p. 431, 1893; Ibid., vol, clxxxv. p. 573, 

 1894. 



VOL. XIV. 2 D 



