The water of these springs is quite sedimentary. Numerous cones of silent springs are seen all around, occasiond by constant accumulations from the sediment of the waters. Some of the springs form craters or basin-shapd tops of several feet in diameter. These springs, after having been active a great number of years, choke up their orifices, and become silent. One which I saw on the bank of the river, calld by some the Steamboat spring, had nearly ceasd to flow. Its dying groans reminded me of a dying butcherd animal. Many of the springs are intermittent of a few seconds alternately. So soon as the gasses are sufficiently accumulated beneath, they are dischargd, often throwing the water to several feet.
Some of these springs are too alkaline to be pleasant to the taste, or even healthy. Others again, have a sufficient amount of acid in combination to render them tolerably pleasant. I believe, however, that none of them are as pleasant as the artificial soda of our shops.
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About fifty miles east of Fort Boyce, along the south side of Snake river and near to it, are hot springs issuing from the plains. At their sources, they are scalding hot. Not far distant from these, on the north side of Snake river, are other similar springs. Fifteen or sixteen miles west of Fort Boyce, at the crossing of Malheur on the emigrant road, are other springs, some of which are so hot that a man cannot bear his hand in them two seconds. All of the hot springs are sulphurous.
From the volcanic character of a great portion of the country lying west of the dividing ridge of the American continent, it may probably be inferd that the water of these springs is heated by internal fires, not very deep-seated.
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The Cascade falls are noticd by some travelers as worthy of attention. Some remarks relative to them may not be altogether uninteresting, as well also to correct some errors of former writers.
Mr. Eby, a late visitor of the falls, informd me that the country above the cascade is so nearly on a level with the country below, that were the rocks that choke up the river at the cascade removd, the water of the river would flow as smoothly and with as little apparent fall, as it does for miles above or below that place.
Immediately above the falls is an apparent subsidence of many acres of timberd land, so that the trees are standing in very deep water. But few of them at present remain. Visitors of the present day are of the opinion that the apparent subsidence is not one in reality, and that the place now submerged was once a bottom land, coverd with a dense growth of fir, and as the rocks precipitated from their stupendous columns into the river at that place, the waters were gradually damd up, so as to overflow the bottom of the river above.
The timber there submergd has become of a siliceous petrefaction, showing the grains of the timber as perfectly as if no such petrefaction had taken place.