222 The Rev. S. Haughton's Notes on Mineralogy. 



Insoluble. Soluble, 



grs. grs. , 



Silica 33-20 13-50 



Titanic acid .... MO 0*31 



Alumina 8-80 2-90 



Peroxide of iron . . . 2'14 060 



Protoxide of iron . . 270 5-70 



Protoxideofmangane.se. 016 0*10 



Lime 5-40 252 



Magnesia 2*76 8-55 



Soda ...... 3-74 2-23 



Potash ..... 0-54 023 



60-54 36-64 



Loss 1*26 1-56 



Total 61-80 38-20 



3. Vesicular Augitic Lava, with cavities lined with white crust. 

 Dunedin, New Zealand. 



This lava, like the last, is divisible into two portions, soluble 

 and insoluble in muriatic acid : — 



Per cent. 



Soluble 40-40 



Insoluble . , , . . 59-60 



10000 

 It contains a large quantity of carbonates, due to metamorphic 

 action. 



Insoluble. Soluble, 



grs. grs. 



Silica . . ... . 3300 924 



Titanic acid . . . . 0'80 0-30 



Alumina . . . . . 9'00 4*44 



Peroxide of iron . . . 2-09 4-07 



Protoxide of iron . . . 1*15 4'43 



Protoxide of manganese . 0*16 0*10 



Lime 8-08 2-13 



Magnesia ..... 3'04 6*09 



Soda 1*76 0-83 



Potash 0-88 021 



5996 31-84 



Gain 0-36 



5960 

 Carbonic acid, water, and loss. . . . 8*56 



-iStO 

 The portion of a lava that is soluble in muriatic acid consists 

 of carbonates, magnetic oxide, and an unknown silicate of alu- 

 mina and soda ; it therefore varies considerably according to the 



