BASALTIC AND IGNEOUS ROCKS. 643 
The only traces of existing fires in the vicinity are found in a hot 
spring on the east side of the Shasty Peak, near a track pursued occa- 
sionally by parties to California. Mr. McKay of the Willammet, who 
has visited it, described it to me as boiling up from among the rocks to 
a height of two or three feet, and says that he has cooked eggs in it. 
The water as it runs off in a small stream has worn the rocks smooth, 
and formed a small basin below, which is much frequented by the 
mountain sheep. 
A mile and a half before leaving the trachytic region, we passed a 
small chalybeate spring. Descending a few yards to a small plain on 
the borders of Destruction River, the spring was observed just around 
on our left. The water oozes out from among the rocks into a basin 
scarcely holding a gallon, and flows down over a small marshy spot 
thickly covered with iron-rust; it is brisk and pungent with carbonic 
acid, and has therefore been called by the trappers soda water. ‘The 
taste is very agreeably acidulous and chalybeate, and no saline or 
alkaline ingredients could be perceived. The temperature is as 
cold as that of the mountain torrent near by. Fifty yards beyond 
the spring, there is a shallow ditch a hundred yards long, contain- 
ing about half a foot of water similarly chalybeate, but less brisk 
with carbonic acid. Our horses drank freely of it, and with good 
relish. 
In the course of the following three days over the granites, talcose 
and hornblendic rocks of the Shasty Mountains, we frequently passed 
dikes or ledges of a porphyritic basaltic lava, very similar to the rocks 
of Hillock Prairie, north of the Shasty Peak. Many were three or four 
hundred feet in width, and some were much more extensive. The 
rock had a dark grayish colour; it was generally cellular and some- 
times so coarsely so as to become a ragged lava. It contained tables 
of feldspar, mostly compound crystals, which were from a tenth to a 
third of an inch long. 
Obsidian or volcanic glass is said to occur in some parts of the 
Shasty region; but we met with none of it. The Shasty Indians use 
this material for their arrow-heads, which they work out with great 
skill. 
Swalalahos or Saddle Hill—On the jaunt to Swalalahos, we as- 
cended for ten miles Young’s River, (a stream entering Young’s Bay, 
on the south side of the Columbia,) and then struck through the 
forests to the south-southeast, twenty-five miles. When at the base of 
