of the Island of Bute. ^ I 



No. 1. Spec. grav. 2*7 10. 



By Ml. J. H. Turnbull. By Mr. Henry S. Thomson^ 



Silica 



Aluiiiiiia 



Protoxide of iron . . 

 Carbonate of lime . 

 Carbonate of magnesia 





6-91 



1-68 

 9065 

 1-00 



IOO-2'I. 



I. 

 5-16 

 1-50 



No. 2. Spec. grav. 2-570. 



Silica 



Alumina 



Protoxide of iron 

 Carbonate of lime . 

 Carbonate of magnesia 



} 



5-70 



1-28 



91-08 



1-17 



99-23 



10017 



99-66 



No. 3. Spec. grav. 2-679. 



Silica 



Alumina .... 

 Protoxide of iron . 

 Carbonate of lime . . 

 Carbonate of magnesia 

 Water, coaly matter and 

 carbonic acid . . . 



} 

 } 



I. 



9-70 



1-12 

 67-42 

 17-31 



4-45 

 100-00 



No. 4. 



} 



64-21 



II. 



72-12 



9-08 



1-12 

 67-00 

 18-06 



4-74 

 100-00 



64-46 



Silica 



Alumina .... 

 Protoxide of iron . . . 

 Carbonate of lime . . . 

 Carbonate of magnesia 

 Water and carbonic acid . 



100-00 100-00 



The silica present is in a state of mechanical mixture. 



These analyses are confirmatory of the main points of the 

 views already stated, and seem clearly to establish the new 

 and remarkable fact, that by the igneous action in these in- 

 stances the magnesia has been driven off from the limestone. 



