146 GEOLOGICAL SURVEY OF THE TEREITORIES. 



full description of it I refer to Professor Bradley's report. A specimen 

 from this group was handed to me for analysis. Composition, irregular ; 

 color, rusty brown; fracture, couchoidal; luster, vitreous: hardness, 

 5.5-6. 



Analysis. 



Per cent. 



Loss at 110° C 4.00 



Loss on ignition 5. 75 



Silica 85.85 



Iron and alumina - , 1. 94 



Lime 1.85 



Magnesia 0.30 



Soda* Trace. 



Potassa* Trace. 



Lithia* Trace. 



99. 09 



The Fountain Geyser is the second in importance in the lower basin, and 

 is centrally situated. It is on a slight eminence, and from it the deposit 

 slopes gradually forward the river, studded with innumerable springs. 

 This geyser was fully described in the report for 1871, so I will pass it 

 by here. Back of the Fountain are the Mud Pufts, which were also 

 fully described last year. 1 wish to insert here an analysis, by Dr. End- 

 lich, of a pink mud from this locality. A portion of the silica is doubt- 

 less combined with some of the alumina as a silicate. 



Analysis. 



Per cent. 



Loss on ignition 8. 65 



Silica 44.61 



Alumina 45. 09 



Magnesia 2. 66 



Ferric oxide , 1. 86 



Lime Trace. 



Soda* Trace. 



10:*. 87 



Between the Fountain Geyser and the Mud Pufis, we find pieces of 

 wood coated with geyserite, which assumed a beaded form, sometimes 

 branching like certain forms of coral. Most of the specimens are trans- 

 lucent and have a vitreous luster. The color is generally a light pin.k. 

 An analysis made by me of this form of geyserite gives the following 

 result : 



Analysis. 



Per cent. 



Water 10.40 



Silica 88.48 



Alumina and iron .88 



Lime .18 



Magnesia Trace. 



Soda* Trace. 



Potassa* Trace. 



Lithia* Trace. 



99. 94 



Wood may be found in various stages of silicification, and if the prob- 

 lem can ever be solved as to the process of silicification, I think a sojourn 

 in the geyser-basins of Fire-Hole Eiver will be of the highest importance 



* By spectroscopic examination. 



