[Illustration: BRIDGE OVER THE SPOKANE RIVER, SEATTLE, LAKE SHORE AND EASTERN RAILWAY.] THE GEOLOGY OF WASHINGTON TERRITORY. HISTORICAL AND STRUCTURAL. I shall not say much about the historical geology of Washington Territory, because it contains some problems which have never been adequately studied, and which I had no opportunity to investigate. It is to be hoped that the regular work of the Government Survey may soon be extended to this important region. Hitherto it has been neglected. A few able geologists such as Joseph Le Conte, Pumpelly, Newberry, Bailey Willis, and some others, have made visits to the country on special errands; but except the treatise of Bailey Willis in Vol. XV. of the Census Reports, and some brief allusions to the country in systematic works on general geology, I had nothing to guide me as to the structure of the country, or the age of its deposits. For all practical purposes, however, I had no difficulty in understanding the work I had to do. [Sidenote: The Western Coast regions younger than the Rocky Mountains and Appalachians.] [Sidenote: An outlying Continent.] [Sidenote: The rise of the West Coast.] All agree that the country west of the Rocky Mountains proper, and including nearly all of California, Oregon, and Washington Territory, is geologically younger than the main range, and younger than the Appalachian country. At the close of the carboniferous period proper, the Rocky Mountain range constituted a separate continent, with a sea covering what is now the main Mississippi Valley, including the wide plains immediately east of the Rocky Mountains, and connecting, probably, with the polar sea, whilst the Pacific Ocean washed the western edge of this Rocky Mountain continent; so that until after that period there were no Wahsatch and Uintah mountains, no Sierra Nevada and Cascade Range, no Coast Range, and, of course, none of the intervening country. It is quite possible, however, that there was a third continent lying west of the present continent in what is now ocean, from whose waste the sediments were derived which were afterwards elevated and became the land now included in the three States bordering the Pacific, whilst the mother continent, which furnished the sediments, sank beneath the ocean. If there were such an outlying continent, additional force is given to the views of Dr. George F. Becker, endorsed by Dr. C. A. White, and to some extent anticipated by Prof. J. D. Whitney, which render it probable on other grounds that the two great lines of mountains, viz., the Sierra Nevada and Cascade Range and the Coast Range, began their upward movement simultaneously during the early ages of the Juro-Trias. The rise of these mountain lines was gradual and marked by reverse movements, whereby, after appearing above the surface, they sank and rose alternately, receiving fresh sediments, which, especially in the Washington Territory region and part of Oregon and California, when