654 OREGON AND NORTHERN CALIFORNIA. 
served. The localities high up the Columbia were not visited by the 
writer. 
Concretions.—In many localities the argillaceous shale contains 
nodular concretions of limestone. These concretions are often very 
regularly spherical, and vary from half an inch to six feet in diameter, 
though if exceeding a foot, the form is more irregular. ‘The size is 
nearly uniform at particular localities: in one place they were about 
half an inch through, or like bullets; a few rods distant they were an 
inch and a half; at another locality, all were two or two and a half 
inches in diameter; at another, the general size was four inches. 
They are often very abundant, and as they fall out from the crum- 
bling precipice, the plain at foot becomes covered with these balls 
of stone. 
The concretions often contain a fragment of wood or a fossil shell, 
a crab’s leg or bones of fish. Yet in some localities no nucleus was 
apparent. Fossils rarely occur in the shale where these concretions 
are found, except they are inclosed in some of the concretions. No 
solid layer of limestone was observed in any part of the sandstone 
formation. These nodules occur along the Columbia, east of Astoria, 
in sufficient abundance to be procured and burnt for ime. They 
were also observed in the shale of Elk River. 
Dip—Displacements.—The layers of sandstone and shale are gene- 
rally horizontal. This is the case along the Columbia River. Near 
Elk River the rock is either horizontal, or dips six or eight degrees to 
the southwest, away from the basaltic ridges. South of the Boundary 
Range, the dip is from twenty to twenty-five degrees to the east-north- 
east, giving the hills a slope to the eastward and abrupt fronts to the 
westward. Across the Clammat Prairie there is a distinct line of 
elevation, as already mentioned, running east and west; the sandstone 
is raised about twenty feet above the plain, and inclines fifteen degrees 
to the northward. It appears then that horizontality is the prevailing 
feature; and that variations from this position are connected with 
the basaltic eruptions of the country. 
The rock has been variously fissured, and it is a singular fact, that 
in many cases the fissures opened have been filled with sands like 
those of the sandstone, so that dikes of solid sandstone actually inter- 
sect the shales. Half a mile above Astoria, a sandstone dike five feet 
wide intersects the bluff from top to bottom, and may be traced follow- 
ing an east-by-south course, across the flat shores to the edge of the 
river. ‘The rock resembles a half-decomposed granite, and seemed at 
