r 



f 



n 



V 



: '-> 



RESTING OX THE TRAIL 



Photograph by L. G. 'P'olsom 



relatively steep front and was convex, 

 highest in the middle, so as to turn the 

 drainage oft to the edges, along each of 

 which a deep canyon had been cut. 



But despite the indications that it had 

 once been fluid, we saw no mud-cracks 

 or other evidence of shrinkage uron dry- 

 ing out, such as one would have expected 

 to find in a mud-flow. Its length we 

 estimated by our pedometer at 2V 2 miles. 

 Its highest part attained an elevation of 

 nearly 1,000 feet, from which point it 

 sloped to about 300 feet at the base. We 

 were not so well able to estimate its thick- 

 ness. But along the edges where it was 

 cut into by the streams a section about 

 50 feet thick was exposed. In the middle 

 it may have been much thicker, both on 

 account of the convexity of the surface 

 and the greater depth of the valley floor. 



Under erosion, this and other similar 

 mud-flows, later found, develop very 

 striking bad-land topography, so that on 

 a bright day one might almost imagine 

 himself to be in western North Dakota 

 if it were not for the streams trickling 

 everywhere from the melting snows. 

 When the mud dries it becomes hard and 

 holds its shape, so that the sides of the 



gullies remain vertical, as they are cut by 

 the streams, and do not crumble away as 

 would softer soil. 



LAVA ALL BLOWN TO FRAGMENTS 



, \Ye were very much surprised at the 

 character of the ejecta close to the crater. 

 Post-cards are current in Alaska show- 

 ing great rocks which are said to have 

 been "hurled from the volcano," and we 

 ourselves had expected to find something 

 of the sort. 



The fact is, however, that the violence 

 of the explosions was so great that every- 

 thing which came out of the crater was 

 blown to "smithereens." Pieces of pum- 

 ice six inches in diameter were hard to 

 find, and the very largest piece we could 

 discover near Mount Katmai was less 

 than nine inches in its longest dimension. 



Xo where was there any flow of lava in 

 connection with the recent eruption. 

 This is due to the fact that the lava as it 

 rose through the throat of the volcano 

 was so heavily charged with gases, mostly 

 steam, under enormous pressure, that on 

 reaching the surface it was either blown 

 into a froth of pumice by the sudden ex- 



40 



