656 OREGON AND NORTHERN CALIFORNIA. 
Bay, there are veins of sandstone in a platform of shale, running as 
shown in the figure here given. A vein 
six inches wide has a course to the south- 
west-by-south, and dips a little to the 
southeast. On one side of the vein there 
= is a branch an inch wide, which is soon 
lost in a mere thread. The sketch is a bird’s eye view, and represents 
a length of eight feet. 
These pseudo-dikes of sandstone, were probably formed after or 
during the deposition of the sandstone while the region was yet under 
water. Fissures were opened, perhaps by the same cause that ejected 
the basalt of the intersecting dikes; and the fissures were filled at 
once by the granitic sands, along with an occasional fragment of shale 
from the walls of the fissure. Their number and irregularity evince 
that these regions have been often shaken by subterranean forces. 
_ The bearing of these facts upon the relative position of the shale 
and sandstone will be perceived; they afford presumptive evidence 
that the sandstone is the upper deposit. Moreover, if this be true, 
there has been a large fault in the line of the Columbia. ‘The sand- 
stone continues to the water’s edge on the north shores, while on the 
south, banks of shale, at least two hundred feet thick, border the 
river; above this height, the shale is covered by the soil. | 
Minerals.—Besides the limestone nodules, no minerals of any im- 
portance were discovered in the tertiary formation, and there is 
little to encourage expectation. ‘There are traces of gypsum in the 
shale near Astoria; and in the same rock on the Bay of San Francisco, 
it is more abundant. Onasmall island in this bay, just northeast of 
the Caquines Straits, Dr. Pickering observed that it had fallen from 
a seam in masses four inches thick, and he states that several tons 
might be procured there. A specimen of fine alabaster, or snowy 
gypsum, labelled John Day’s River, was handed me by Mr. Drayton, 
who received it from Mr. Gray ; nothing more definite is known of the 
locality. 
Many of the concretions in the shale are deeply stained with iron, 
and a trace of iron pyrites was occasionally met with. 
Some of the limestone nodules near Astoria, contain a centre or axis 
of a brown calcareous material, having an external crystalline form, but 
a granular texture within like the prismatic concretions from Glendon, 
New South Wales. They have a rhombic prismatic shape, like the 
Australian concretions; yet it is evident that the prisms are made from 
