117 
Dana, but bear a much closer resemblance to those inhabit- 
ing the north-eastern states. It is possible that they are 
from a more recent deposit; but the presence of a few re- 
markable forms which are common to the two localities 
renders it more probable that there is no great difference in 
- their age.” 
I have given, in full, all that Frémont says regarding this 
locality, as it presents us with the first discovery of strata 
of the remarkable character of which I am now treating, and 
is therefore of special interest. Bailey’s report, contained in 
the same volume, merely mentions and figures the principal 
forms he detected. 
The only other description of this locality and these re- 
markable deposits, fortunately, is a much more complete and 
scientific one. It is thatof Dr. J. 8. Newberry, as Geologist 
of the Expedition, under Lieuts. R. S. Williamson and Henry 
L. Abbot, which explored the route for a Railroad, from the 
Sacramento Valley to the Columbia River in 1855, and will 
be found in Vol. VI. of the Pacific Railroad Survey Reports, 
At page 44 and subsequent pages of the Geological Report, 
Dr. Newberry gives a description of the Geology of the Des 
Chutes Basin, which is essentially as follows. It must be 
remembered that the Des Chutes and Fall River mentioned 
above, are one and the same. 
The Des Chutes basin consists of a series of plateaus, 
having varying elevations from 4,000 to 22,000 feet above 
the level of the sea, separated by subordinate ranges of 
voleanic mountains. These plateaus are usually covered by 
a floor of Trap, which extends in a smooth sheet from fifty 
to a hundred and fifty feet in thickness, unbroken except by 
and at the cafions of the various streams which, as a general 
thing, flow from the interior to the ocean at right angles to 
the coast line. Beneath this bed of Trap, is the whitish or 
light-colored material consisting of the silicious remains of 
Diatomaceze we are considering, sometimes occurring as a 
single bed only, sometimes as a series of beds locally inter- 
calated with thin beds of Trap. These Infusorial strata, as 
they have been called, are cut, in many places by the Des 
