64 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



It might have been supposed that a series of rocks so well dis- 

 played and so full of interest would long ere this have been exa- 

 mined and described in minute detail. But they can hardly be said 

 to have yet received, as a whole, the attention they, deserve. I am 

 unwilling to add to the length of this Address by references to the 

 various authors who, each in his own measure, have added to the 

 sum of our knowledge of the subject ; but I cannot refrain from an 

 allusion to one or two of the more important of these pioneers. 

 First and most important of all were the classic descriptions of 

 Ami Boue. As a young medical student at the University of 

 Edinburgh, Boue had imbibed from Jameson a love of mineralogy 

 and geognosy, and for some years he spent his leisure time in per- 

 sonally visiting most parts of Scotland to study the geological struc- 

 ture of the country. As the result mainly of his own observations, 

 he drew up an account of the Old Ked Sandstone which, when it 

 appeared in his ' Essai,' marked the first great forward step in the 

 investigation of this section of the geological record.^ He was the 

 earliest observer to divide what he calls the " roches feldspathiques et 

 trappeennes " into groups according to their geological position and 

 mineralogical character, and to regard them as of igneous origin and 

 of the age, or nearly of the age, of the red sandstone of Central 

 Scotland.^ Of later writers who have treated of the volcanic rocks 

 of the Old Eed Sandstone my old friend Charles Maclaren deserves 

 special recognition. His survey and description of the Pentland 

 Hills embodied the first detailed and accurate investigation of any 

 portion of these rocks, and his ' Geology of Eife and the Lothians ' 

 may still be read with pleasure and instruction.^ Boue indicated 

 roughly on the little sketch-map accompanying his ' Essai ' the chief 

 bands of his felspathic and trappean rocks of the Old Eed Sandstone, 

 but their position and limits were more precisely defined in Mac- 

 culloch's ' Geological Map of Scotland,' which was published in 1840, 

 five years after the sudden and tragic death of its author. The 

 observers who have more recently studied these rocks have been 

 chiefiy members of the Geological Survey, and to some of the more 

 important results obtained by them I shall refer in the sequel. 



Up to the present time, however, no connected account has been 

 given of the volcanic rocks of the Old Eed Sandstone. The brief 

 outline which I now offer to the Society is the first attempt of this 



^ ' Essai Geologique"sur I'Ecosse' (Paris, uo date, but probably 1820). 



2 O-p. cit. p. 329. 



3 ' Geology of Eife and the Lothians,"' 1839. 



