THE NATIONAL GEOGRAPHIC MAGAZINE 



131 



In the latter 

 branch the climax of 

 the activity of the 

 whole district is to be 

 found in the two re- 

 markable features de- 

 scribed below — Fall- 

 ing Mountain and 

 Novarupta Volcano. 

 We were astonished 

 to find that this 

 branch has no head, 

 but continues round 

 by Mt. Katmai and 

 back to the main val- 

 ley under the slopes 

 of Knife Peak. 



The mountains, thus 

 surrounded by a com- 

 plete ring of vents, 

 are so cut up by 

 faults that we named 

 them the Broken 

 Mountains. They are 

 bisected by a smaller 

 branch valley, also 

 full of vents, stretch- 

 ing across from No- 

 varupta. Activity oc- 

 curs in yet another 

 branch on the oppo- 

 site side of the main 

 valley well down to- 

 ward the bend. The 

 total length of all of 

 these smoking valleys 

 is 32 miles. The area 

 is 70 square miles, the 

 average width being 2 

 miles. 





: 



Photograph by J. W. 



EXPLORING A STEAMING FISSURE 



With the steam so thick that one cannot see his way, 

 wonders where he is comma: out 



Shipley- 

 One often 



COMPARISON WITH THE YELLOWSTONE 

 PARK 



With these dimensions at hand, it will 

 be interesting to compare the valley with 

 the Yellowstone Park. In the Yellow- 

 stone there are about 4,000 hot springs 

 and a hundred geysers scattered over an 

 area of some 3,000 square miles. The 

 geysers, which are the most interesting 

 feature, occur in several isolated geyser 

 basins, whose total area is hardly 20 

 square miles. The largest of the geysers, 

 which play but seldom, shoot up a column 

 scarcely exceeding 300 feet in height. 

 The column of Old Faithful, which is the 



only geyser the tourist can count on see- 

 ing in action, is about 100 feet high. 



In the Alaskan Valley there are in con- 

 stant action thousands of vents whose 

 columns exceed that figure. The columns 

 of several of the largest vents may, when 

 conditions are right, ascend more than 

 5,000 feet into the air or, under the influ- 

 ence of the winds which sweep the valley, 

 trail along the ground for two or three 

 miles. 



WHY THERE ARE NO GEYSERS 



One of the questions most frequently 

 asked by persons interested in the region 

 is whether or not there are geysers. 



