38 GUIDEBOOK OF THE WESTERN UNITED STATES. 



remnants of ancient volcanoes that have been subjected to Ion*' 



erosion and worn down to their sohd cores or hard central parts, 

 called plugs because they fill the opening through wliich the lava 

 had been ejected. 



At the University of Oregon, in Eugene, is the largo collection of 

 fossils made. by Prof. Thomas Condon, who in his day did much to 

 interpret the geology of Oregon. 



A stage hno up McKenzie River, the largest tributary of the 

 Willamette, which enters the valley near Eugene, leads to the Blue 

 River mining district and gives access to the hunting and fishing 

 grounds about the Three Sisters, snow-clad peaks that carry the 

 largest glaciers in Oregon. The extent of these glaciers during the 

 glacial epoch has not been determined. An ice stream of considerable 

 size probably once occupied the basin at the head of the McKenzie, 



vidence of glaciationhas been recognized in the lower McKenzie 



Valley. 



Will 



more 



ing in a body of water wliich Prof. Condon named Willamette Sound. 



Railroad cuts on a branch now being built from the main hue at 

 Eugene across the Coast Range to Coos Bay will no doubt display 

 good sections of the Eocene sediments of which this part of the rantre 

 IS largely composed. Another branch runs southeastward from 

 Eugene up the valley of the Middle Fork of the Willamette to Oak 

 Ridge. This branch when extended across the Cascade Range and 

 connected with a line already built from Weed, Cal., to Kuk, Oreg., 

 by way of Klamath Falls will form the main fine of the Southern 



cue to Weed. This route will avoid the deep cross- 

 drainage valleys of Umpqua, Rogue, and Klamath rivers, will make 

 Crater Lake National Park more easUy accessible, and will be superior 

 in scenic and geologic interest to the route now followed. 



The rock underlying Eugene is a f ossihferous gray sandstone of Ter- 

 tiary age. 



The University of Oregon is passed on the right (southwest) a 

 mile from the station at Eugene. A mile farther on may be seen 



an abandoned quarry of the fossiliferous sand- 

 Springfield Junction. gtoj,e^ ^iso on the right. Beyond it the raih'oad 



SaS"3i2miS'' P''^^^^ through an area of basalt hills, suc- 



ceeded by shales. At Springfield Junction the 

 shales give place to a gray sandstone full of marine shells like 

 those seen nearer Eugene. This fossiliferous sandstone may be 

 seen in an old quarry on the right side of the railroad. Half a 

 mile beyond Springfield Junction are bluffs of fragmental volcanic 

 material (tuff aceous conglomerate) , which continue for nearly a mile. 

 This material is cut by dikes of basalt, which may be seen along the 

 banks of the river. After passing these the raikoad takes final feave 

 of WiUamette River and in a climb of 20 miles sm-mounts the Io^nt 



