5 



mation about these springs, it will be remembered, is calcareous, 

 and to this fact is due its distinctive character, so different from the 

 silica formations which prevail elsewhere in the Park. " The over- 

 hanging bowls which these deposits build up are among the finest 

 specimens of Nature's work in the world, while the water that fills 

 them is of that peculiar beauty to be found only in thermal springs." 

 Cleopatra Spring, Jupiter Terrace, Pulpit Terrace, Minerva Terrace, 

 are among the most interesting and beautiful of the active springs. 

 One of the most beautiful is a pool filled with pellucid water in vio- 

 lent ebullition. The sides and bottom of the basin are formed of pure 

 white travertine, while the varying depths cause the water to appear 

 all shades of blue and green, from a deep peacock blue in the deeper 

 parts of the bowl, to the lightest of Nile greens in the shallow re- 

 cesses. In wandering about the terraces, one is much impressed 

 with the brightly tinted basins about the springs, and the red and 

 orange colors of the slopes overflowed by the hot waters. These 

 colors are due to the presence of the microscopic plants, alga; of 

 several forms and species. In the cooler springs and channels simi- 

 lar vegetation forms the bright green, orange or brown mem- 

 brane-like sheets, or masses of jelly without apparent vegetal struc- 

 ture. Silken yellow filaments are found in bowls and channels of 

 the hottest springs. Words fail to convey an adequate idea of the 

 massive marble-like terraces, rising tier upon tier, and the exquisite 

 coloring of their sides and the margins of the bowls filled with 

 steaming hot water of most magnificent iridescent hues. 



The silicious formations are similar, although not raised in ter- 

 races so grand or imposing, simply because the formation of silicious 

 sinter is much slower than the formation of the travertine, and 

 because the region seems to be of later geologic age. Many of the 

 geyser cones are bee-hive in shape, of a white adamantine-like 

 appearance, and are, as a rule, delicately colored by pale greens and 

 pinks of exquisite variation. The many hundreds of springs of the 

 Upper Geyser Basin, where they are seen at their best, are generally 

 characterized by the transparent clearness of the water, which 

 appears of varying shades of blue and green, according to the depth 

 and amount of light admitted. Morning Glory Spring is one of the 

 most beautiful springs of the Park, with a lunnel-sha ed cone sug- 

 gesting the flower, and with walls most delicately colored. 



Black Sand Basin is, however, most interesting for our j:ur- 



