A Report on Washington Territory

by William Henry Ruffner

LOWER SNOQUALMIE FALLS, 268 FEET HIGH, ON LINE OF SEATTLE, LAKE SHORE AND EASTERN RAILWAY.

The rocks and minerals of the Cascade Mountains.The core of these high ranges is chiefly rock originally stratified, which has been metamorphosed by heat, and perhaps inside of all, with branches bursting out at various places, are plutonic rocks which have never been stratified. This is the state of things on the top of the Cascade Range, near Snoqualmie Pass, as well as on some subordinate peaks and ranges. On Mount Logan, the Denny Mountain, etc., are large bodies of syenitic granite whose age I have no means of determining. Associated with this are quartzites of fine grain, and extremely hard, porphyries, and serpentinoid and chloritic rocks of different sorts, in which are imbedded the magnetic iron ores; and also large beds of crystalline limestone, both fine and coarse grained. Crossing these, at various angles, are veins containing the precious and base metals.

The metamorphic rocks of doubtful origin.Whether these rocks are Palæozoic or Archæan in their origin, or whether they are simply the metamorphosed strata of the upper Juro-Trias, or the lower Cretaceous, is a question for future study. These plutonic and metamorphic rocks are believed to extend through the mountainous region lying north of the Columbia River; and they are reported also in the Cœur d'Alene Mountains. It is quite certain that on both flanks of the Cascade Mountains we find in their natural state Cretaceous conglomerates, sandstones, and shales bearing coal, at least in their upper beds. The deposits on the east side of the mountain have been much grooved and denuded, until we find only small areas of the Cretaceous strata on the Yakima and the Wenatchie rivers, and the Peshastan ridge between, with a patch of the coal-bearing rocks on the Yakima, and another on the Wenatchie. On the west side of the mountain range, the Cretaceous and coal-bearing areas are much larger.

The coal beds.The coal deposits of all the Cretaceous regions of the West are regarded as belonging to the Laramie period which closed the Cretaceous age, and constitutes a transition period between the Cretaceous and Tertiary. But I do not regard this question as settled. The inferior lignites of the Rocky Mountains, and the semi-lignites which constitute the upper beds of the Washington Cretaceous coal properly belong to the Laramie period; but to include the underlying bituminous coals in the same group may be a matter of question. More will be said in reference to these coal beds under the next head. The Western coal-bearing rocks begin on outlying mountains, standing at the west foot of the main Cascade Range. These outlyers are irregular in size, height and direction; but many of them are 1,000 to 1,500 feet in height, and they are found in groups, separated by denuded spaces, from the Cascade Mountains to the Pacific Ocean, and from the Canada line nearly to the Columbia River. The largest and most important field, however, lies south of the Snoqualmie River and between Puget Sound and the Cascade Mountains. Some of the coals found in the most southern part of the field, and on the Coast Range, are referred to the Tertiary period.

A smaller and wholly undeveloped field lies on the Skagit River, and another on, and west of Bellingham Bay. Similar beds are found on Vancouver's Island. Coal-bearing strata are found also on the Chehalis, Des Chutes, Nisqually and Cowlitz rivers. Whilst some of these southern and western strata are referred to the Tertiary period, there has been no systematic study of their geologic relations.

The volcanic mountains and their great activity.It seems to be settled, however, that the lofty volcanic mountains which form conspicuous features in the scenery of the Cascade Range, were active in the Tertiary period, and not only built their own crests 9,000 to 15,000 feet high, but inundated much of the surrounding country with lava to an amazing breadth and depth. In this region, Mount Baker, Mount Ranier (also called Mount Tacoma), Mount St. Helens and Mount Adams in Washington Territory, and Mount Hood in Oregon, were the centres of the grandest operations; and so continued for ages.

We see gigantic results of this activity in the cañonThe wonderful cañon of the Columbia River. 1,000 to over 3,000 feet deep, which the Columbia River has cut through this volcanic matter in its passage through the Cascade Mountains. This volcanic deposit consists of brown basalt, which in cooling crystallized into vertical, polygonal prisms, or columns, which have been sculptured by the weather into endlessly varied forms, beautiful, fantastic, and grand; altogether presenting a scene, or succession of scenes, for twenty-five miles, such as can nowhere else be equaled on the American continent, unless it be near by, on a tributary of the Columbia, the Des Chutes River of Oregon.

The great sheets of basalt.This great pile of basalt was built up by a succession of overflows of lava, the joints of which are plainly visible. The basaltic area, though perhaps thickest here, continues with a thickness of 1,000 to 1,500 feet up the Columbia for hundreds of miles; indeed the whole plateau, or prairie country of East Washington, which is a quadrilateral of some 200 miles in diameter, is but a continuation of the great lava-sheet seen at the Cascades and the Dalles. Through it the Columbia and Snake rivers have cut deep channels; and other, though shallower channels, have been cut across the surface of the plateau by departed streams.