APPENDIX C. MINERALOGY. 139 



Silica 79.30 



Peroxide of iron - -- - 8.95 



Alumina .. ... - 1.50 



Carbonate of lime - 1.10 



Sulphate of lime, with strong traces of sulphate of soda and 



chloride of sodium - 4.65 



Water 4.50 



100.00 



