Wright.] 
432 
[Jan. 1, 
it bends abruptly- and runs due north for about 250 miles, leaving 
the open country, which stretches westward through southern Idaho 
and Oregon to the base of the Cascade mountains, to make its way- 
through the more mountainous region at the east base of the Blue 
mountains around which it flows. I know of no scientific explo- 
rations of this portion of the Snake valley, and the Oregon Short 
Line Railroad avoids it by crossing the Blue mountains, but the 
accounts of earlier explorers represent the mountain ridges as com- 
ing close to the river, and the latter as running through precipitous 
canons deeper and more inaccessible than those of the lava plains 
of the Upper Snake valley. It seems probable that the cutting 
down of some barrier in this northern course — very likely as you 
suggest some lava flow that stretched across its valley — would ac- 
count for its present relatively rapid slope. 
The so-called placer bars which are found along its present course, 
often considerably higher than the present stream, not only in this 
region, but at various points above, also point to a recent rapid 
deepening of its bed. They carry gold in an extremely fine state 
of division and their material is generally much finer than the or- 
dinary placer gravel, containing but few pebbles and these not en- 
tirely of quartz but sometimes of slate. They have evidently been 
brought from the mountains to the eastward at a much higher stage 
of the river, where its stream was longer and more rapid than at 
present. 
The Nampa beds are, however, older than these gold-bearing 
gravels and probably older than the ancient gravels of the Upper 
Boise basin at the southwest base of the Sawtooth mountains, which 
Mr. Becker, in his report on precious metals for the tenth census, 
compares with the deep gravels of California, from the fossil plants 
which they contain, from their great depth of 250 feet, and because 
they are said to be capped by basalt flows. I did not visit this basin 
but assume that the gravels are younger than the Nampa beds be- 
cause of the higher levels which they occupy. I must confess that 
at present I see no evidence which would decide whether the Nam- 
pa beds are late Tertiary or early Quaternary except that furnished 
by the drill hole, which if authentic would be in favor of the latter. 
To the west of this region in southern Oregon, and along the Des- 
chutes and John Day valleys at the east base of the Cascades, both 
Pliocene and Quaternary deposits are found. The latter in the 
