OUR GREATEST NATIONAL MONUMENT 



241 



have presented a spectacle, if it could 

 have been seen through the impenetrable 

 black cloud that rose from its surface, 

 far surpassing the weirdest image of the 

 infernal regions ever conjured up by poet 

 or preacher in an effort to picture the 

 place of everlasting torment. 



The spectacle presented by this tre- 

 mendous outflow of incandescent sand 

 was not seen by human eye. But even 

 the stiff, cold mass lying on the ground 

 where its movement ceased is one of the 

 most impressive features of the Katmai 

 National Monument (see page 228). 



A CUBIC MIEE OF INCANDESCENT SAND 



Not only did the flow continue down 

 the main arm of the valley toward Nak- 

 nek Lake for 17 miles, but it also ran 

 back across the divide behind Novarupta 

 Volcano and completely encircled the 

 Broken Mountains, coming down a side 

 valley under Knife Peak to join the main 

 flow again several miles downstream. 

 More surprising yet, a quantity of it was 

 poured out high up in Katmai Pass, 

 whence it ran both ways, sending one 

 tongue down to the base of Observation 

 Mountain on the Pacific side of the 

 range, while another flowed down into 

 the main valley between Cerberus and 

 Falling Mountain (see map, page 227). 



Its greatest length is thus 20 miles, 

 while its greatest breadth is 9 miles. The 

 total area covered is 53 square miles. 



Over most of this area the depth of the 

 flow is so great that no indication of the 

 original height of the ground remains. It 

 is impossible, therefore, to estimate the 

 thickness of the mass. Only around the 

 edges and near its terminus can one find 

 any stream canyons or fissures that cut 

 through it (see page 229). 



The deepest canyon exposes a section 

 about a hundred feet thick, but there are 

 the best of reasons for supposing that its 

 thickness must be much greater than that 

 over the larger portion of the valley. It 

 seems quite safe to estimate its total 

 volume as greater than a cubic mile ! 



A cubic mile of incandescent sand ! 

 The figure is so large as to pass compre- 

 hension. If a gang of contractors with 

 steam-shovels should start to load it onto 

 flat cars, they would find that before they 

 had finished thev would have filled a train 



that would reach entirely around the 

 world and still leave a considerable pile 

 of it untouched. 



Pulverized as it is, the material may 

 justly be compared with crushed stone, 

 for in composition it is similar to granite. 

 If it had been permitted to crystallize deep 

 down in the interior of the earth, it would 

 have become granite. 



In seeking to gain some conception of 

 the magnitude of the operation by which 

 it was produced, we may inquire how 

 long it would take our stone-crushers to 

 pulverize a similar mass of granite into 

 road-making material. The answer is 

 that the sand flow is equivalent to the 

 output of all the stone-crushers in the 

 United States for a period of one hun- 

 dred years ! 



OBJECTIVES OE OUR EAST EXPEDITION 



In piecing together a narrative of the 

 events of the eruption that gave birth to 

 the Ten Thousand Smokes, we have in a 

 certain sense put the cart before the horse, 

 for the sifting of evidence that has made 

 the preceding account possible required 

 a large amount of time and study. 



The various aspects of volcanism de- 

 scribed by previous expeditions are so 

 exceptional and so helpful to an under- 

 standing of many puzzling problems of 

 the volcanic mechanism that I felt our 

 findings^ were too important to stand 

 alone without corroboration by other ob- 

 servers. _ The scientific world" would in- 

 deed be justified in some skepticism over 

 such remarkable reports until they were 

 independently confirmed by other ob- 

 servers. 



After a survey of the field, it was de- 

 cided that no other organization was so 

 well equipped to handle some of the 

 varied problems encountered as the Geo- 

 physical Laboratory of the Carnegie In- 

 stitution. Accordingly, this institution 

 was invited to send a party with the Na- 

 tional Geographic Expedition of 1919, 

 under a cooperative agreement, whereby 

 the National Geographic Society under- 

 took to assume the field expenses of the 

 party, while the Geophysical Laboratory 

 agreed to work up the results on the 

 return. 



The production of a moving-picture 

 record of the wonders of the region occu- 



