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Rh or angle. With this exception the blocks are flat. Occasionally one gets thrown off, and so the columns never appear at any great height above the earth; but their fragments strew the river-bank for a long distance.

This basaltic outflow evidently came from Mount St. Helen. On any of the sand-bars in the Lewis or the Cathlapootle River, which debouches into the Columbia on the opposite side, are to be found water-rolled fragments of pumice-stone in abundance; and there are seasons of high-water which bring down from Mt. St. Helen by some of its streams—the Cowlitz in particular—so much white volcanic ash as to render the water milky in its appearance. It is somewhat remarkable that while on the Oregon side the basalt covers every stratified rock or sedimentary deposit, on the Washington side the hills are immense deposits of coarse gravel or sand, and water-rolled stones.

About in the central portion of the Wallamet Valley are some gravel beds of no great thickness; while in Washington Territory, along the Columbia and in the Puget Sound region, the soil is gravelly to an extent which renders it almost unfit for cultivation. Did the facilities which the Sound offered for drainage prevent the deposit of soil-making matter during the period of its submergence?

There are evidences, in the elevated beaches of the Oregon and Washington coast, of great changes of water-level over that portion of these countries west of the Cascades. At Shoalwater Bay, for instance, where the action of the surf has undermined large portions of the bluff shore, breaking it off, there are, exposed to the eye of any observer, vertical sections of sedimentary deposit one hundred feet above the present sea-level. Mixed with this deposit, and