GEOLOGICAL SURVEY OF THE TEEEITOEIES. 187 



Tv^ater rose gradually in the basin, and that there were occasional at- 

 tempts at eruptions, which failed, preceding the actual eruption. A 

 specimen of the water brought back was as clear as when bottled at the 

 eeysers, showing no deposit whatever. There was not sufficient for a 

 quantitative analysis. It contained 835f| milligrams of solid matter to 

 the liter, consisting in the main of silica. Chloride of lime and sulphate 

 of magnesia were present in small quantity, and there was also a trace 

 of iron present. The glaring white deposit, which extends over both the 

 upper and lower basins, is principally geyserite, a variety of opal. The 

 forms it assumes here are similar to those found in Iceland. The speci- 

 mens vary in color, form, and texture. The majority are of an opaque 

 white, or grayish color. In the lower basin some pink specimens were 

 obtained which are translucent ; other specimens are of a greenish gray. 

 Some of the white pieces were subtranslucent ; others were pearly and 

 enamel-like. Specimens from the geyser-cones have generally a cauli- 

 flower-like form, and break very easily ; others are beaded, and still 

 others covered with small stalagmitic processes. The texture varies 

 from porous to compact, and some pieces are very easily reduced to 

 powder. The majority of the deposit which extends through the basins 

 is porous, and arranged in layers. The geyser-cones are generally very 

 compact, and very often have an enamel-like coating. From some of 

 the springs masses were obtained that are filamentous and stalactitic. 

 Some pieces seem as though the surface had been enameled and then 

 suddenly allowed to contract, leaving small, irregularly shaped plates 

 of enamel attached to the main mass by pedicles. In the lower basin 

 we found smooth balls, which, on being broken, were found to be com- 

 posed of concentric layers of geyserite of a homogeneous structure. 

 Others, which were beaded or otherwise fantastically fashioned on the 

 outside, were found to be very irregular in their structure. The latter 

 were generally of a pink color. A specimen of white geyserite, of 

 cauliflower-like form, hardness of 5, and specific gravity 1.866, contains — 



Silica 83. 83' 



Water 11. 02 



Chloride of magnesium 4. 00 



98. 85 

 Analyses of geyserite from other parts of the world are as follows : 



White geyserite from Iceland, f analysis hy Damour.J 



Silica - 91. 23 



Water 8. 97 



100. 20 



Geyserite from Iceland, f analysis hy Forcliliammer.J 



Silica 84. 43 



Water : 7. 88 



Alumina 3. 07 



Iron « . = 1. 91 



Lime 0. 70 



Soda and Potassa 0, 92 



Magnesia - J .". . 1. 06 



99. 97 



