Mr. Bryce on the altered Dolomites of the Island of Bute. 21 



No. 2, is the hard crystalline marble, having the crystals in distinct 

 flakes — more remote from the dike and less altered than No. 1. 



No. 3, is the unaltered limestone from the middle of the quarry, remote 

 from the dike — an average specimen. It corresponds to No. 2, in Mr. 

 Macadam's report. 



No. 4, is the altered limestone from contact with the overlying trap at 

 Ascog mill ; it is an impure, dark coloured rock, of earthy aspect, and 

 very like the trap which rests upon it. 



The matter termed silica and alumina, is what was insoluble in muri- 

 atic acid. 



No. 1. I. 11 



Analyses by Mr. J. H. Turnbull. Analyses by Mr. Henry S. Thomson. 



Specific gravity, 2'710 



^"^^""^ 1 6-91 5-16 5-70 



Alumina, j 



Protoxide of iron, 1-68 1-50 1-28 



Carbonate of lime, 90-65 91-08 



Carbonate of magnesia, I'OO 1"17 



100-24 99-23 



No. 2. I. n. 



Specific gravity, 2-570 



^'^^^! 1 1-94 0-28 0-28 



Alumma, j 



Protoxide of iron, 0-52 0-56 



Carbonate of lune, 96-48 98-76 96-58 



Carbonate of magnesia, 1-23 2-24 



Silica, . 



10017 99-66 



No. 3. I. II. 



Specific gravity, 2-679 



,, . \ 9-70 9-08 



Alumma, J 



Protoxide of iron, 1-12 1-12 



Carbonate of lime, 67-42 72-12 67-00 



Carbonate of magnesia,17-31 1806 



Water, coaly matter, ^ . .► . ^. 



' , •' . . '> 4-45 4*74 



and carbonic acid, J 



100-00 100-00 



No. 4. 



f;''''\ 164-21 64-46 



Alumma, ) 



Protoxide of iron, 642 6-60 



