134 



The Ohio Journal of Science [Vol. XIX, No. 2, 



NO OLD MATERIAL FROM WHICH MUD FLOW COULD HAVE 

 BEEN FORMED. 



If, therefore, this mud flow is to be interpreted as a secondary 

 deposit produced by the working over of the original ejecta 

 of some previous eruption, it will be necessary to suppose 

 that some of the preliminary events of the present eruption, 

 such, perhaps, as the melting of a large quantity of snow, 

 occurred in such a way as to soak up a mass of old mud lying 

 on the mountains and start it down into the Valley. With 

 this possibility in mind, we searched the mountains for some 



Photograph by R. F. Griggs 



MAT OF VEGETATION REDUCED TO CHARCOAL BENEATH 



THE MUD FLOW. 

 The original surface of the soil has been uncovered by erosion. 



remnants of an ancient stratum of mud. But not the slightest 

 indication of any such deposit could be found. It was our 

 custom to examine and measure sections, cut by streams 

 through the layers of ash, wherever found. In all the sections 

 examined the ash from Katmai lay directly on bed rock or 

 old soil as the case might be, with no such mud deposit inter- 

 vening. Yet it would be altogether impossible for every trace 

 of so extensive a deposit to have been turned into mud and 

 carried into the Valley. Any deposit thrown into the air from 

 a crater would be spread, in small quantities at least, over a 



