334 GEOLOGY OF BUTE. 



clay is always interposed, and is a remarkable feature in the 

 beds. It is very striking to pass at once from this clay, 

 mostly unfossiliferous and without stones, to a rich shell bed 

 in which stones also are contained. The absence from Arran 

 of this laminated bed may perhaps be accounted for by the 

 exposure of the situation ; for if it was formed by the trans- 

 port of fine mud from the ends of glaciers which reached 

 the coast of the period, and this seems the most probable 

 origin for it then on situations more open and exposed it 

 would be swept away. 



List of Species. 



142. These fossiliferous clays may be seen at many places on 

 the Bute coast, besides the two chief localities we have named 

 as Kames Bay, Ettrick Bay, where they are now nearly 

 denuded by the sea; parts of Eothesay Bay, and indeed 

 wherever there are sheltered places suited to their preserva- 

 tion. They have been long carefully studied by the Rev. A. 

 MacBride. Later and more extended lists are given in a 

 series of papers, not yet completed, by Rev. H. W. Crosskey 

 and Mr. D. Robertson, in the Transactions of the Geological 

 Society, Glasgow. The following list of the species found at 

 Kilchattan has been kindly supplied x to me by Mr. D. 

 Robertson. It contains all the fossils from these beds known 

 to him, except those of the Ostracoda; on these a monograph 

 is now in preparation : 



Fislws. 

 A few vertebrae. 



Conchifera. 



Anomia ephippium, .... Lin. 



Pecten Islandicus, .... Mull. 



My til us modiolus, .... Lin. 



Nercula tennis, Mont. 



Leda pernula, var., .... 



