Columnar Section of Willamette 

 Valley and Upper Umpqua Basin. 



Columnar Section of the Coast 

 Range and Coast of Oregon. 



Pliocene basalt 



^1, 



San Lorenzo tuffs of Silverton 

 and Eugene. 1,000' 



Arago formation 

 tuffaceous and arkose sandstone 

 of Umpqua Basin, coarse basic 

 tuffs farther north on Santiam 

 River. 



10,000' 



Bedrock complex 



Marine Pleistocene terraces, 50' 



Elk River formation, 300' 



Merced formation, 50' 



Empire formation, 500' 



Monterey formation 



sandstone and clay shale of Newport. 



2,000' 



Seattle formation 



tuffaceous sandstone and shale 



of Nehalem and Yaquina Bays. 



5, 000' 



San Lorenzo formation 

 tuffaceous sandstone and shale 

 of Upper Nehalem and Yaquina 

 Rivers. 



5.000' 



Arago formation 

 tuffaceous lignitic sandstones 

 and shales of Coos Bay district 

 becoming more and more tuffa- 

 ceous to north and grading into 

 coarse tuffs and basaltic flows 

 of Wilson River and South Ne- 

 halem River. 



10,000' 



Bedrock complex 



