TOPOGRAPHY AND LIFE ZONES OF OREGON [ 2.3 ] 



East of the Cascades the general topography is that of a great inland 

 plateau, rapidly rising from its lower edge along the Columbia to attain 

 elevations of x,ooo to 9,000 feet. 



In the extreme northeastern corner of Oregon is found some of the most 

 spectacular scenery in the State. There a spur of the Rockies crosses into 

 Oregon in a generally northeast to southwest direction, and through it, 

 the Snake River, which forms the eastern boundary, has carved a gigantic 

 canyon that in depth is equal to the Grand Canyon of the Colorado and 

 is bordered by perpetually snow-capped mountains in both Oregon and 

 Idaho. Those on the Oregon side, known as the Wallowas, are a miniature 

 Glacier Park and contain almost innumerable icy lakes, often perched 

 high on the precipitous slopes in little glacial cirques. To the south and 

 west this spur, known generally as the Blue Mountains, extends to the 

 vicinity of Prineville, where it is lost in the sage plains with a gap of 

 only a few miles between it and the Cascades to the west. (See Plates 



2. tO 4.) 



The two major streams in Oregon that flow into the Columbia River 

 east of the Cascades are the Deschutes and the John Day. The Deschutes 

 rises in the central Cascades, gathers the waters of the lakes about 

 Bachelor Butte, Diamond Peak, and the Three Sisters, and, flowing almost 

 straight north after it emerges from the mountains, receives additional 

 water from the eastern slope of the Cascades, and finally reaches the 

 Columbia a few miles east of The Dalles. (See Plate 5.) The John Day 

 rises well in the eastern part of the State, draining many of the spurs of 

 the Blue Mountains before it enters its rocky gorge and turns north to 

 join the Columbia not many miles east of the Deschutes. 



In the south, all of Klamath County and the western edge of Lake 

 County are drained by many small streams that finally empty into the 

 Klamath Lakes. From Upper Klamath Lake, the Klamath River flows 

 south and west to carve a gorge through both the Cascade and Coast 

 Ranges before it empties into the Pacific in northern California. The 

 Klamath and the mighty Columbia are the only rivers that have suc- 

 ceeded in cutting through the Cascade-Sierra Nevada Range, which, 

 except for these two gaps, extends unbroken by rivers from the Canadian 

 border to Mexico. 



The great shallow alkaline lakes of Harney and Lake Counties rem- 

 nants of vastly greater bodies of water of bygone ages are highly im- 

 portant physical features from the biologist's point of view. They are 

 created by the waters draining from the slopes of the Blue, Warner, and 

 Steens Mountains and other smaller ranges. Some of these lakes occa- 

 sionally evaporate completely in dry cycles, a condition that has been 

 distressingly acute during the past few years, but several times within 

 historic ages they have filled again, following increased rainfall, and have 

 become a haven for myriads of migratory waterfowl and other birds. 



