SURFACE FUSION OF LAVA 



143 



by spreading, the crater was filled and overflowed, Liberating the most remark- 

 able blasts of hot gas, which were shot down the slope as at Martinique, com- 

 pletely devastating its path. 



That the extruded lava was softened by heat and rendered viscous is shown 



Figure 1. — Basaltic Lava from, San Salvador, Central America 



This basaltic lava was erupted by the Crater El Pinar of San Salvador volcano June 

 7, 1017, in the republic of San Salvador, Central America. 



Dr. S. Calderon sent the specimens to Washington, and states that they were "col- 

 lected in pockets of scoria? formed by the escape of the gases, being found on all very 

 steep slopes where the current of lava formed cascades." 



It is believed that the hot gases escaping from the lava-flow into the pockets met the 

 gases of the air and reacted so as to become hot enough to melt the adjacent lava. 



The upper portion of the specimen is dull red. It is a part of the lava-flow the lower 

 portion of which has been melted by the hot gases in a pocket. 



by the fact that the steam-torn lava was bent during the eruption. Portions 

 of the bent lava were broken, but the continuity of the mass indicates that 

 most of the lava at the time of its eruption was softened by heat to a highly 

 viscous condition. 



