114 



The Ohio Journal of Science [Vol. XIX, No. 2, 



the other smokes by which it is surrounded. Like them it is 

 an absolutely new volcano, having burst forth in a situation 

 where no volcanic activity had ever previously occurred. Its 

 crater, which is 0.8 mile (1.25 km.) in diameter, is occupied 

 by a plug of cooling lava that recalls the remarkable ''spine" 

 of Mt. Pelee. This plug is, however, much less conspicuous, 

 being much broader, 800 ft., (250 m.) than high, 200 ft., (60 m.) 



Photograph by P. R. Hagelbarger 



DETAIL FROM THE LARVA PLUG AND CRATER RIM OF 



NOVARUPTA. 

 The broken pile of lava is about 200 feet high. 



From this plug of lava are still given off great quantities of 

 gases which in calm weather ascend 10,000 ft. into the air, 

 forming great clouds that obscure the sky for miles around 

 (see page 113). The history of Novarupta began with a period 

 of explosive activity, during which it threw out a great mass of 

 ash and pumice, forming deposits 50 feet thick or more in 

 the vicinity of the vent. This explosive activity, which is 

 shown by the sequence of the deposits to have occurred before 

 that of Katmai, was much less violent than that of its greater 



