CHEMICAL ANALYSES. 



183 



2. MARL, SAN PEDRO RIVER. 



Matter insoluble in hydrochloric acid 



Alumina and peroxide of iron 



Carbonate of lime 



Carbonate of magnesia 



Soluble salts, as — 



Sulphate of lime, chloride of sodium 



Moisture 



A fresh water deposit. 



3. LIMESTONE, CHIRICAHUI MOUNTAIN. 

 Color, blue. Specific gravity, 2.74. 



Found. 



Silica and insoluble clay 5.020 



Alumina and peroxide of iron 2.928 



Carbonate of lime 4.864 



Carbonate of magnesia .324 



Alkaline salts 270 



Moisture and traces of organic matter 1.000 



14.388 



Calculated. 



35.30 



20.33 



33.77 



2.22 



1.35 



6.94 



99.90 



4. LIMESTONE, ORGAN MOUNTAINS. 



Physical characters same as 3. 



Insoluble silicates 38.00 



Alumina and peroxide of iron 12.17 



Carbonate of lime 37.65 



Carbonate of magnesia 3.16 



Alkaline salts • 1.75 



Moisture and organic matter 7.25 



99.98, in 100 parts. 



5. TRACHYTE, PELONCILLO HILLS. 



Specific gravity, 2.56. 



Silica 69.470 



Alumina 22.600 



Peroxide of iron .720 



Carbonate of lime 2.154 



Carbonate of magnesia .300 



Alkalies 4.666 



99.910, in 100 parts. 



