Dec., 1918] The Great Hot Mud Flow 133 



again en masse in such a manner as to permit the formation of 

 such a tremendous quantity of mud all at once. Indeed, 

 I can imagine no process of nature by which the present 

 hardened tuff could be changed back into liquid mud. 



But the condition of the burned trees is unequivocal proof 

 of the recent date of the mud flow. It occurred so recently 

 that there has been no time for the protruding parts of trees 

 to decay since they were killed. Even the small twigs of the 

 dead trees are still in place, giving positive evidence that the 



Photograph by R. F. Griggs 

 STUMPS OF TREES BURNED OFF BY THE MUD FLOW. 



Exposed by later erosion. It is to be observed that the mud was so cooled by 



contact with the soil that it did not burn the stumps clear to the ground. 



The roots protected by a few inches of soil were not burned at all. 



mud flow must have occurred very recently, (see pages 126 

 and 129). There is everywhere a conformity between the mud 

 flow and the overlying ashfall that of itself negatives the 

 possibility of an interval of erosion between them. There 

 are, moreover, occasional evidences that the mud was still fresh 

 and liquid at the time of the ashfall. There are a number of 

 places where local adjustments of the mud occurred after the 

 ashfall. In such situations a secondary flow of mud lies above 

 the layers of ash, (see pages 110, 136 and 140). All lines of 

 evidence thus converge to show that the mud flow occurred 

 immediately before the explosion of Katmai. 



