Page:Centennial History of Oregon 1811-1912, Volume 1.djvu/235



THE CENTENNIAL HISTORY OF OREGON ISa

fact that tliis baseiaent roek of our Oregon Cascade range was once Cretaceous sea bed. This age is, so far as yet discovered, only represented in Oregon by shells and corals, but the possibilities of its fossils are by no means exhausted.

This period gave the world its fii'St palm trees and its first hardwood trees, as the oak, maple, hickory and walnut. It was during the Cretaceous that rep- tiles reached their greatest development. And it is supi)Osed to be the age in which the small inferior type of earlier mammals evolved into the multitutle of higher forms with which the next period opens.

Its climatic conditions were such that a very even temperature prevailed over the earth, so that zones of plant and animal life seem almost unknown. Dana says: "During the Cretaceous a warm climate still prevailed over the earth even to the poles." So that cycads flourished in Greenland, Spitzbergen, Alaska, British America, Montana, Siberia, Sweden, China and India; and the sequoia, the family of the California big trees and redwoods, was represented by many species throughout the north polar regions.

It is not at all impossible that some young geologist may find remains of Cre- taceous forests in Oregon, or while w'andering through some water-worn ravine, may come across an old Cretaceous tone bed, proving that Oregon, too, had her great, clumsy small-brained dinosaurs ; or he may find the bones of the long, bat- like finger of the pterodactyl, the lai-ge flying reptile that flitted from crag to peak. And why should the Rocky mountain region monopolize the Ci-etaeeous birds with their rows of sharp, recurved, reptile-like teeth? For these Cretaceous fossils we would look among the mountains or along the foothills of the regions of Shoshone and Siskiyou.

THE EOCENE AGE

In this age the ocean was excluded from eastern Oregon and Washington. The Eocene age dawned upon a region of lakes. Whether there were many or few of great extent, has not yet been determined and perhaps we may never know, for such large areas have since been covered by sheets of lava and later sediments that the older records have, in some regions been hopelessly buried and in others entirely destroyed. Eastern Oregon and Washington and southern Idaho must have been very beautiful in the early Eocene, for the Blue mountains were far grander then than now, they were much nearer the rugged vigor of their "topo- graphical youth" before erosion had worn down their lofty summits, and before lava floods had filled their valleys and transformed their foothills into a high ta- ble land of volcanic rock. Lindgren has said in his Gold Belt of the BJue Moun- tains :

"Take away the lava flows which cover the flanks of the Blue mountains and you would see rising to imposing heights almo.st from sea level, and separated by a lower gap, two great, roughly circular mountain groups — the Eagle Creek mountains and the Blue mountains proper." Prom these imposing mountains large lakes stretched out in every direction. The climate was damp and warm, well fitted to stimulate the growth of vegetation. The grand old coniferous trees were well represented and the hardwood trees as the oak, ash, elm and maple were increasing in numbi'rs and variety. Palm trees were never again so scattered over the whole earth as in the Eocene age, and the Northwest had its s