Page:Centennial History of Oregon 1811-1912, Volume 1.djvu/248

 f The Dalles.

There were glaciers in tlie McKenzie valley and Mohawk valley. The Willam- ette valley was high table land with glaciers reaching to its borders. Puget sound was dry, with glaciers plowing across its valley near the present cities of Seattle and Tacoma. Dana tells us: "The river channels off the California coast indicate two or three thousand feet of added height to the coast, probably during the glacial period." The Straits of Fuca and the Columbia were then wearing deep channels "now twenty miles out at sea." Coos bay has its off-shore channel, giving added evidence of the coast during the Glacial age.

Dr. Diller tells us that during the Glacial period a grand snow peak towered above the present Crater lake. This mountain has been christened Mount Mazama, and once rivaled Shasta and Rainier in grandeur ; it was not only a snow peak, but was also an active volcano during the Glacial age. Some of the lava that rolled down the sides of the mountain and cooled into volcanic rock, were later scratched and scarred by the ice streams or glaciers that crept slowly toward the valleys. Finally Dr. Diller tells us that the whole summit of the mountain fell into the chasm beneath, a chasm left by the outpouring of molten material from within. This chasm is one of the wonders of our state ; for after engulfing the whole upper part of the mountain there still remains a crater six miles wide and four thousand feet deep. If man was living in Oregon as he was in Europe at this time the shock that accompanied the engulfing of this grand snow peak and volcano must have been to the poor superstitious savages a most frightful expe- rience.

How long, how continuous or severe was this Glacial age upon our coast is not accurately known, but it must have been of great duration. Most of the animals probably migrated southward, not alone on account of cold, but to an even greater extent because the forests and green herbage had moved toward the south, and the herb-eating animals must follow vegetation, and if the herfbiverous ani- mals migrated the flesh eaters must follow their prey. So there were very few animals that could have remained during the Glacial age.

When at last after the long period of cold had passed and the glaciers of Ore- gon had slowly retreated toward their glistening snow peaks, and the more tender herbage, shrubs and trees had crept northward, neither the animal nor vegetable life that returned to Oregon was the same. The great lapse of time, hundreds of thousands of years, and the increasing struggle for existence had worked through the laws of evolution to produce different animals and a different vegetation. The camel seems to have disappeared, and the herds of wild horses to nave re- turned no more. The mammoth elephant, judging from the frequency of its fossil remains, must have been a very common sight during this post-glacial time in Oregon and Washington.

The forests had lost much in richness and variety of forms. Many genera that flourished so hixuriantly in the upper Miocene or Mascal Flora have never returned to our Pacific Northwest.

We have seen that the Pliocene and Glacial were times of great elevation, but with the coming on of the post Glacial time, there was a gradual sink- ing of the northern part of the United States. Not only did the Pacific States lose much of their western border, recently acquired from the ocean, but the sea gained upon the land until the water stood several hundred feet higher upon the coast than it does today. If the reader ^^ashes to follow this