Feb., 1919] Nitrogen Content of Volcanic Ash 



219' 



as in (1) and (4). Sample 33, collected by Dr. Griggs in 1916, 

 was found to contain twice as much total nitrogen as (1), 

 in which seedling grass was growing, but the acidity and 

 ferrous sulphate content was so high as to preclude the pos- 

 sibility of plants surviving. 



Martin Creek, the principal affluent of Katmai River,, 

 flows in from the west and brings the drainage waters from 



TABLE IV. 



NITROGEN CONTENT OF RIVER DEPOSITED PUMICE AND ASH, KATMAI RIVER, 



MARTIN CRERK CAMP. 



the southerly slopes of Mt. Martin and Mt. Mageik. This 

 area was to the windward of the Volcano at the time of the 

 eruption and consequently received but a slight fall of ash and 

 pumice. The pre-eruptive vegetation along its head- waters still 

 persists, and the frequent floods coming down throughout the 

 summer might be expected to scatter this vegetation far and 

 wide over the everchanging ash and pumice bars of the lower 

 Katmai Valley. Just below the junction of Martin Creek 

 with Katmai River lies an extensive flat covered by river 



