ASSOCIATED IGNEOUS ROCKS OE THE AYRSHIRE COAST. 785 



Prof. Seelet thought that many rocks, when examined over a 

 broad area, might be regarded as of metamorphic origin, and yet 

 might sometimes be intrusive, and seem to be igneous in small 

 exposures, without ever having been connected with flows of lava. 

 He thought that Mr. Mallet's theory of vulcanicity supported the 

 adoption of this view. 



Mr. Hudleston objected that Prof. Seeley had not denned the 

 terms volcanic and metamorphic. 



Prof. Duncan pointed out that originally the position maintained 

 by Dr. Geikie was that grauwacke had been altered in situ into 

 serpentine, and this Prof. Bonney had shown to be altogether in- 

 admissible. 



Prof. Judd insisted on the importance of not confusing the 

 definitions of igneous and metamorphic rocks. He said that the 

 serpentine dykes of Forfarshire were almost certainly of Carboni- 

 ferous age. 



Rev. E. Hill, from personal examination of the district, con- 

 firmed Prof. Bonney's views as to the intrusive character of the 

 rocks in question. 



Prof. Bonnet, in reply, said that he thought the intrusive rocks of 

 Ayrshire were very probably of Carboniferous age. He asserted that 

 there was nothing like a transition of the serpentine into the rocks 

 into which it is intruded. He did not accept Mr. Mallet's views 

 as to the formation of certain rocks by crushing action. 



Q.J. G. S. No. 13(3. 3g 



