144 



THE NATIONAL GEOGRAPHIC MAGAZINE 



. Photograph by D. B. Church 



A PORTION OF THE} ROCK SLIDE} FROM THE SLOPES OF NOISY MOUNTAIN 



Unlike Falling Mountain, one of the phenomena of the Valley of Ten Thousand Smokes, 

 Noisy Mountain, in the upper Katmai Valley, gives off no steam, yet there is a constant rum- 

 ble of falling rocks from its sides. Note the conical piles of rock in the middle distance (see 

 page 143). 



found places, however, on these piles 

 clean of all debris, where steam could be 

 seen issuing directly from the solid rock, 

 just as one sees it high up on the moun- 

 tain side. 



If such evidence were sufficient to per- 

 mit one to draw positive inferences he 

 might conclude that Falling Mountain is 

 really a mild sort of explosive volcano in 

 which the explosions occur in solid rock 

 rather than in liquid lava. But the pres- 

 ence of a similar active mountain in upper 

 Katmai Valley (Noisy Mountain), from 

 which no steam issues, would make one 

 hesitate in drawing such a conclusion. 

 A more critical study of these curious 

 mountains than was possible, with our 

 limited facilities, ought to yield valuable 

 results. 



NOVARUPTA VOLCANO * 



Directly opposite the precipices of Fall- 

 ing Mountain lies Novarupta, the great- 



* The name suggested by Mr. Folsom is here 

 published for the first time. 



est of all the vents in the valley. This, 

 though newly formed at the time of the 

 big eruption, is one of the world's largest 

 volcanoes. It is, indeed, a new volcano, 

 differing materially from most of the 

 "new" vents that appear, in that it is not 

 located on the top of an old volcanic 

 mountain, which had erupted before and 

 was in reality only dormant (see p. 138). 



On the contrary, it burst through in a 

 new place along the margin of the old 

 volcanic complex, appearing not in igne- 

 ous rock, but in sedimentary sandstone 

 adjacent to former igneous extrusions. 

 This vent is located not on a mountain 

 top but in the bottom of a valley, which 

 before the eruption gave no indication of 

 the volcanic forces beneath. 



Novarupta apparently began with an 

 explosive violence surpassed in this dis- 

 trict only by Katmai itself, for quantities 

 of its pumice are scattered over an area 

 ten miles in diameter, forming deposits 

 in places more than fifty feet deep (see 

 page 145). In these deposits cinders 



