124 
THE GEYSERS. 
or bolus, and on one side of it I observed, what 
appeared to me, a curious mineralogical produc¬ 
tion: it was imbedded in a hard kind of rock, 
but was of itself exceedingly brittle, and appa¬ 
rently fibrous; looking much like asbestos, but 
materially differing from that mineral in its ex¬ 
tremely fragile nature. On going to the foot of 
the hill, near the spot wdiere the waters of the 
Geyser join a cold stream, among the numerous 
rills which the heated water had formed, I met 
with some uncommonly beautiful specimens of in¬ 
crustations. Every blade of grass and every leaf 
or moss that was washed by these waters, w r as 
clothed with a thin covering of the same siliceous 
substance as the great basin was composed of, but 
of so delicate a nature that it was scarcely pos¬ 
sible, even with the utmost care, to bring any of 
them away perfect. I remarked, in particular, 
a Jungermannia (asplenioides) so beautifully 
coated with this incrustation, that it looked as if 
it were a model of the plant in plaster of Paris. 
One specimen was so protected under the shelter 
of larger plants incrusted together, that 1 was 
able to convey it in safety to Reikevig. The 
plants I met with by the side of the river, which 
I had not remarked before, were Carex Rellardi 
and a new 7 species, Koenigia islandica in great 
profusion, and Funaria hygrometrica. Leaving 
the river, I walked over several vast mounds of 
