EXTINCT VOLCANO — ATWOOD 



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FiGDKH 4. — The last glacial landscape. The U-sliaped valleys which notch the present rim 

 were produced during this final ice invasion. The dotted line indicates the location of 

 the rim. 



FiGOKE 5. — The present Crater Lake located in the giant caldera, formed by the collapse 

 and engulfmeut of Mount Mazama. The Wizard Island cinder cone developed after the 

 disappearance of the mountain. 



Figure 6. — A generalized cross-section of the region today. The alternating layers of till 

 and volcanic material record the story of the growth of Mount Mazama. The dotted 

 lines mark the several stages represented in the preceding drawings. 



