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LOCAL SECTIONS 



excepting the upper beds, which weather arid split into prismatic blocks, from one 

 inch to one foot in thickness, and stand out in the form of turrets. 



From the summit an immense plain can be traced, apparently about thirty miles 

 in extent, its uniformity broken at intervals of a few miles by these curious, isolated 

 peaks of sandstone, most of which seem to have about the same elevation. 



The plain is elevated about seven feet above the water. 



About five miles above the Dalles, thirty-five feet of sandstone appears on the 

 left bank of the river, and continues for a few hundred yards. Not far from this 

 place there rises one of those isolated peaks, two hundred feet above the plain, like 

 some time-worn castle, with turrets, towers, and battlements. 



Two and a half to three miles further, the sandstones of F. 1 are again exposed ; 

 at first on the right bank, twenty-nine feet high ; then on both sides, from fifteen 

 to fifty feet high. The upper layers are thinly laminated ; the lower are thicker, 

 but soft and easily worn by the current, so that the superior strata often project, 

 even as much as ten feet beyond the base. Here the soil is sterile and sandy, 

 bearing a growth of small pine and scrubby oak. 



The strata rise to the northwest, so that half a mile beyond this last exposure 

 the sandstone is ninety-five feet high, presenting a mural face to the river. At 

 several points the beds are intersected by vertical fissures, that traverse the rocks 

 from top to bottom, and divide the strata into large square blocks. About eight 

 feet above the river, a band of sandstone, of brick-red colour, contrasts strongly 

 with white sandstone beneath. 



Between two and three miles higher up stream, the rocks show themselves to the 

 height of one hundred feet ; here the dip begins to be reversed, and the rocks gradually 

 decline to thirty feet, about one mile below Fortification Rock. This remarkable 

 peak is situated on the right bank of the river, with an elevation of one hundred 

 and fifty-five feet. On the northwest face is a perpendicular escarpment ; on the 

 southeast, there are a series of offsets and abrupt descents to the level of the plain. 

 On the top, its length is about one hundred yards ; its width, fifteen to twenty feet. 



The inferior beds, composing Fortification Rock, are thick-bedded white and 

 brown sandstones. At forty feet, the sandstone is red and ferruginous for twenty 

 feet, passing upwards into a variegated rock, with brown, red, and white streaks, 

 ten feet thick ; over this, white and brown sandstones are again repeated. The red 

 beds are hard and massive, without lines of stratification. 



A little over a mile above Fortification Rock, sandstone is again seen, sixteen 

 feet high. At the base it is soft, and of a deep red hue, with a few thin layers 

 of more compact, chocolate-brown sand-rock, passing upwards into variegated sand- 

 stones, like those on Snake River. 



Three miles further is Eagle Rock, which is a perpendicular wall of sandstone, of 

 thirty feet ; the lower layers yellow, surmounted by the red bands of the preceding 

 section, then yellow and brown layers, containing ferruginous concretions, with 

 fine-grained yellow sandstone on the top, some layers of which are ripple-marked. 



The current has here also worn away the inferior strata, leaving the upper layers 

 jutting out ten feet, like an entablature, supported at intervals by heavy columns, 



