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ANNUAL REPORT SMITHSONIAN INSTITUTION, 1935 



Pumice Point (8). — Across Steel Bay to the east is Pumice Point, 

 easily identified from almost any position on the rim because of its 

 large white pumice face. On closer inspection, however, it is dis- 

 covered that there is more than pumice on Pumice Point (fig. 10). 

 Interbedded in the volcanic material are layers of glacial till and old 

 soil. The sequence of events has evidently been one of glaciation, 

 vulcanism, and renewed glaciation, followed by an interval during 

 which soil developed and then by another period of vulcanism. 



PUMICE 



SOIL ZONE 



STRIAE 

 A/je'E. 



STRIAE 



10 FEET 



FiGDKB 10. Two 



jlacial stages at Pumice Point. A soil zone appears in the upper por- 

 tion of the younger till layer. Locality 8. 



The upper portion of the younger till layer is a dark-colored soil 

 zone containing an abundance of vegetal material, much of it charred. 

 The existence of the soil layer on the steep pumice talus slope was 

 first suggested by a band of vegetation which appeared on an other- 

 wise barren hillside. By removing the veneer of pumice, the mois- 

 ture-retentive soil zone was discovered. The relationships here are 

 similar to those on the rim south of the Watchman, although the 

 carbonized material at Pumice Point is limited to small fragments. 

 Future excavations may uncover larger and better-preserved repre- 

 sentatives which, it is hoped, can be identified. The real significance 

 of the soil zone in the story of Mount Mazama is the time interval 



