Scientific Results of the Katmai Expeditions of the 

 National Geographic Society. 



III. THE GREAT HOT MUD FLOW OF THE VALLEY 

 OF TEN THOUSAND SMOKES.* 



Robert F. Griggs. 



As we explored the Valle^'^ of Ten Thousand Smokes, the 

 first thing that attracted our attention, when we could look 

 beyond the smokes themselves, was a curious line that encircled 

 the Valley almost like the high water mark of a flood. Above 

 this line were the ordinar}^ gray ash slopes, below it was a 

 great mass of compact hard tuff of a terra cotta color quite 

 different from the ordinary ash. 



Examination disclosed the fact that the floor of the Valle}^ 

 is covered with a massive deposit of enormous thickness, which 

 has no counterpart on the surrounding hills. The interpreta- 

 tion of the character and origin of this deposit was, for a long 

 while, our chief problem as we explored the Valley and its 

 branches, for its evident peculiarity at once excited our 

 curiosity. 



The difficulty was not that its relations were obscure, for 

 they are so obvious as to suggest the interpretation at first 

 sight. The trouble was that this evident explanation was so 

 seemingly impossible that we were altogether unwilling to 

 accept the testimony of our senses until the evidence became so 

 overwhelming as to eliminate the possibility of further doubt. «* 



Since returning from the field, we have held the matter in 

 reserve, until we could thoroughly digest the evidence and talk 

 it over with some students of volcanism in whose judgment we 

 had confidence. When the matter was first put before these 

 men, it was met with the most violent opposition. They 

 uniformly reacted to the proposition exactly as we had ourselves 

 when we first encountered it in the field. But in the end, when 

 the evidence was presented and all objections answered, with- 

 out exception they accepted the interpretation as the necessary 

 consequence of the facts. 



*Copyright, 1919, by National Geographic Society, Washington, D. C. All 

 rights reserved. 



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