a2 THE TRUCKEE AND HUMBOLDT VALLEYS. 
have been overlooked. The fact that it is increasing in depth’ 
while Pyramid is said to be decreasing, seems to indicate 
that it is of recent origin and occasioned by some accidental 
deflection of the Truckee from its legitimate course. The 
fresh water of the river is soon deteriorated by admixture 
with that of the lake, which like all similar sheets, devoid of 
outlets, is brackish and unpleasant to the taste. The most 
showy plants of the Truckee Valley, in addition to those 
already mentioned, were a gigantic Thelypodium often ris- 
ing to a height of six feet, two species of Mentzelia (Jevicau- 
TM and albicaulis) a species of Hosackia, and two of Cleome, 
and Sida. Near the mouth of the river occurs a remarkable 
deposit of infusorial earth. It is found encased in the cal- 
careous tufa so prevalent in this vicinity. Under this lies 
the basaltic rock. The "chalk," as it is here called, is one 
hundred feet in width and forms a perpendicular bluff nearly 
forty feet in height from the stream, which at this point is 
very deep. The whole deposit is very free from impurities 
and upon microscopical examination, by my brother, proved 
to be composed entirely of fresh-water forms. 
From the Truckee to the Humboldt Valley there is about 
a day's hard riding through deep sands and deserts devoid 
of water, where only grows a depauperate form of sage 
brush (Artemisia), or the equally dreary grease wood 
(Obione). The hills in sight are of volcanic origin, and are 
covered with loose and blackened scoriaceous rocks, occa- 
sionally encased in tufa. There is not a vestige of a tree, 
shrub or herb, with the exception of the ashy colored sage or 
the singular Effedra (anti-sypAilitica). The first and only 
object that awakens any interest is the group of hot springs. 
There are some fifteen or twenty of these presenting differ- 
ent degrees of temperature. One spring indicated 2019 
Fah., while others were positively cool. The water is beau- 
tifully clear, but contains salts in solution which render it 
unpalatable. It is, when cooled, however, preferable to most 
of the villainous decoctions of the sixty-three elements, 
