PEALE.] 



CAUSE OF DEPOSITION — GEYSEEITES. 



401 



Our experience with the waters collected in 1878 shows that the 

 waters from various springs differ upon this point. The following table 

 will show at a glance the condition of the different specimens : 



Spring and locality. 



la 



^a 











" -, rt 







fn 



14.56 



10.60 



7.84 



53.76 



Condition of water when tbe bottles were opened 

 at the end of throe years. 



Jug Spring, Lower Fire-Hole Basin — 

 Echinus Geyser, Gibbon Geyser Basin. 

 Pearl Geyser, Gibbon Geyser Basin — 



Opal Spring, Gibbon Geyser Basin 



Perfectly clear; no deposit; alkaline in reaction. 



Perfectly clear ; no deposit; acid in reaction. 



Perfectly clear ; has a deposit of gelatinous silica, 

 2 tablespoonfuls to the imperial gaJlon ; alkaline 

 reaction. 



This water presented the same opalescent appear- 

 ance as when bottled ; no deposit was found at 

 the bottom of the bottle ; alkaline reaction. 



This would seem to prove that the mere fact of cooling has little to 

 do with the throwing down of the silica, and that it is not due to the 

 amount of silica in the water.* 



The precipitation in tlie case of the water from the Pearl Geyser may- 

 be due to some chemical reaction taking place after the bottling of the 

 water. Ordinarily the formation of the siliceous sinter or geyserite 

 must be explained by the evaporation of the water as it flows from the 

 springs or falls from the geyser. We must remember, however, that we 

 have examined but a few of the many springs in the Park, and what 

 may be true of the few cannot be arbitrarily stated as applying to all 

 the others. 



APPEARANCE OF GEYSBRITES AND MODE OF FORMATION. 



The deposits of the springs and geysers of the Yellowstone Park agree 

 in general characters with those from other regions of siliceous springs. 

 They are of almost innumerable variety, and to describe them here would 

 be impossible. A few of the forms are shown in the accompanying- 

 plates (Plates XLIII, XLIV, and XLV), which have been engraved 

 from photographs of the specimens. A very common form is that in 

 which the general resemblance to amass of cauliflower is striking; snch 

 specimens are seen in a and 6, Plate XLIV. In the center of the plate 

 (c) a similar formation is seen coating a piece of wood. The fracture of 

 such specimens is very uneven, and the structure when they are broken 

 is very irregular. On drying, they break readily into coarse granular 

 pieces. They occur mainly in the vicinity of geysers where there is a 

 fall of water. Where the surface is bathed in steam constantly they are 

 usually pearly on the surface. In some places the surface has a porce- 

 lain-like apjjearance; in others a metallic appearance, as in the depos- 

 its of the Bronze Geyser. Where the flow from the spring is gentle 

 a laminated structure is found. The layers are usually very thin. Some 

 pieces resemble the fossil teeth of some huge herbivorous animal. In 

 /, h, and i, Plate XLIV, and to the right d, in Plate XLIII, such speci- 

 mens are illustrated. The orifices of geysers are usually beaded, and 



"Le Conte, in his Elements of Geology, page 100, says that it is not trno that silica 

 deposits only on drying, "for the Yellowstone geyser waters, * * deposit abun- 

 dantly by cooUnfj, evidently because tliey contain much more silica than those of Ice- 

 land." Wo have in another place proved that the silica is about the same. 



26 H, PT U 



