124 



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



TUFF OF VALLEY SIMILAR TO KATMAI MUD FLOW, BUT FORMED 



BEFORE THE EXPLOSION. 



There was no such difficulty in the case of the Katmai Mud 

 Flow, for in the last spasms of the eruption great quantities of 

 finely divided mud were thrown out on top of the coarse ash 

 and pumice deposited in the earlier stages of the eruption. 

 Part of this, wetted up perhaps by the heavy rains that followed 

 the eruption, slumped down off the ash covered slopes into a 



Photograph by D. B. Church 



A SECTION OF THE KATMAI MUD FLOW. 



Contrast with the section of the Great Mud Flow given on page 132. Here the 

 mud flow occurred after the ashfall which lies beneath it on the original 

 surface of the ground whose irregularities the strata follow. The bushes 

 show no sign of burning, either here or where they protrude through the mud 

 flow. Stratified ash here fifteen feet thick. 



