The Guardians of the Columbia / Mount Hood, Mount Adams and Mount St. Helens - John H. Williams

Fort Vancouver in 1852.

Another glance, as the next long geological age passes, and we perceive a second step in the making of the West. It is the gradual uplift of a thin sea-dike, separating the two islands first disclosed, and stretching from the present Lower California to our Alaska. It is a folding of the earth's crust that will, for innumerable ages, exercise a controlling influence upon the whole western slope of North America. At first merely a sea-dike, we see it slowly become a far-reaching range of hills, and then a vast continental mountain system, covering a broad region with its spurs and interlying plateaus. "The highest mountains," our school geographies used to tell us, "parallel the deepest oceans." So here, bordering its profound depths, the Pacific ocean, through centuries of centuries, thrust upward, fold on fold, the lofty ridges of this colossal Sierra-Cascade barrier, to be itself a guide of further land building, a governor of climate, and a reservoir of water for valleys and river basins as yet unborn.

Seining for salmon on the lower Columbia.

Behind this barrier, what revolutions are recorded! The inland sea, at first a huge body of ocean waters, becomes in time a fresh-water lake. In its three thousand feet of sediment, it buries the fossils of a strange reptilian life, covering hundreds of thousands of years. Cycle follows cycle, altering the face of all that interior basin. Its vast lake is lessened in area as it is cut off from the Utah lake on the south and hemmed in by upfolds on the north. Then its bed is lifted up and broken by forces of which our present-day experiences give us no example. Instead of one great lake, as drainage proceeds, we behold at last a wide country of many lakes and rivers. Their shores are clothed in tropical vegetation. Under the palms, flourish a race of giant mammals. The broad-faced ox, the mylodon, mammoth, elephant, rhinoceros, and mastodon, and with them the camel and the three-toed horse, roam the forests that are building the coal deposits for a later age. This story of the Eocene and Miocene time is also told in the fossils of the period, and we may read it in the strata deposited by the lakes.