Dec., 1918] The Great Hot Mud Flow 137 



on the impossible assumption that the whole of every slope 

 tributary to the Valley furnished its share of the mud. Whereas 

 it is manifest, from its gravitational relations and the position 

 of the high mud marks, that the mud could by no chance have 

 come from more than a small fraction of the watershed, (7 

 square miles). The contrast between the Great Mud Flow 

 and the Katmai Mud Flow in this matter is very striking 

 indeed, for in that case the collecting ground, (5 square miles), 

 was eight times as great as the area at present covered by the 

 mud, (0.6 square miles). See map, page 138. But let us waive 

 this difficulty and go on with the consideration of the situation 

 assumed. 



NO WATER SUFFICIENT TO LIQUIFY THE MUD IF THE MATERIAL 



WERE PRESENT. 



To transform such a vast quantity of dry tuff or dust into 

 mud would require an equally vast quantity of water. The 

 volume of the mud flow, while not accurately known, is of 

 the order of one cubic mile. To hold this quantity of solid 

 material in suspension would require at least a cubic mile of 

 water. Where could it have come from? The only possibility 

 is that the heat of the approaching eruption might have melted 

 a great mass of ice and so furnished the requisite water. To 

 melt such an enormous block of ice would require a stupendous 

 quantity of heat, but the energy of the erupting volcano was 

 probably many times more than sufficient for this. The 

 volcanoes are so heavily covered with glaciers that it is not 

 improbable that there may be a cubic mile of ice on their drain- 

 age area. The trouble is that the volcanoes are still ice-clad 

 at the present time. There is no indication of their having 

 carried within recent geological time larger glaciers than 

 those that still cover their flanks. They bear as many and as 

 large glaciers as their inactive neighbors east and west. One 

 of the remarkable features of the eruption was its small effect 

 on the glaciers of the Volcanoes. There are two miles of ice 

 cliff in the rim of Katmai crater, remnants of glaciers which 

 were beheaded, but not melted, by the eruption. The remains 

 of these glaciers cover every hollow in the mountain. The most 

 extensive of them all stretches down into the Valley of Ten 

 Thousand Smokes, where it meets the mud flow. Mageik, 

 likewise, has a notable snowcap which extends up to and around 



