68 GEOLOGY OF SW. IDAHO AND SE. OEEGON. [bull. 217. 
Idaho-Oregon boundary. These remnants of formerly much more 
widely extended strata indicate the great amount of denudation that 
lias occurred throughout an extensive region. 
Broad and comparatively gentle elevations and depressions of the 
once horizontally stratified rocks occur also in other portions of the 
region examined, as, for example, in the neighborhood of Harney and 
Burns. The rocks beneath the extensive valley in which Malheur 
and Harney lakes are situated slope upward in the hills and moun- 
tains about the borders of the basin, as is well shown in the walls of 
the canyons on the west side of Stein Mountain, in the Crow Creek 
Mountains, on the border of the canyon of Rattlesnake, in the hills 
to the west of Burns, and at several other localities in the same region. 
In general, all about the Harney Basin — as it is convenient to term 
the great depression in which Malheur and Harney lakes are situated, 
and of all of the country drained by them — the rocks are upraised. 
This basin, however, is not a simple saucer-shaped depression, but has 
irregularities, and is due to the association of several upheavals and 
depressions. The broad, gentle undulations in the rocks just referred 
to are, in some instances, a hundred or more miles across, and are 
promising structural features in reference to the hope of obtaining 
an artesian water supply. 
In addition to the broad and usually somewhat indefinite swells 
and depressions referred to above, and others of similar nature but of 
smaller size, are certain well-defined upward folds or anticlines, and 
equally characteristic downward folds or synclines. These are similar 
in shape and analagous in the manner in which they were produced to 
the folds or corrugations that may be made by pushing one side of a 
pile of rugs toward its center, or, on a still smaller scale, by forcing 
together the sides of a pile of newspapers so as to compress them into 
folds. In the region under consideration there are several examples 
of such folds, but, as is commonly the case on all land areas, the 
relief of surface produced in the manner referred to has been greatly 
modified by erosion. The upward folds particularly have been cut 
away, leaving for the most part only their basement portions. 
A striking illustration of a great upward bend, involving bedded 
lava sheets with an aggregate thickness of fully 5,000 feet, and also 
a great but unknown thickness of stratified sedimentary deposits 
beneath them, is furnished by the northern portion of Stein Moun- 
tain and the several parallel — nearly north-south — ridges to the east 
of it, and north of Alvord Desert. The larger features of the rug- 
ged belt of country referred to are seemingly due to the erosion of 
a great anticlinal fold, the longer axis of which trends about north- 
east and southwest, but this conclusion is here stated tentatively, 
as sufficient time was not available for more than a hasty exami- 
nation of a part of the region. The hard layers of compact basalt in 
the truncated remnant of the fold now form the sharp-crested ridges 
