258 Russell — Massive-Solid Volcanic Eruptions. 



" bread-crust bombs" were thrown out. It is of interest to add 

 to this short list of volcanoes which have erupted material in 

 a massive-solid condition, another example, from which lava 

 was discharged in the three or four ways illustrated by Pele, 

 and also gave origin to a stream of lava. 



The volcano referred to is one of five of modern date (post- 

 Glacial) situated on the east border of Pauline Lake in the 

 south-central part of Oregon, which was visited by the writer 

 during the summer of 1902. A view of the interior of the 

 crater, showing a rough but generally level surface surrounding 



Fig. 3. Crater of a volcano near Pauline Lake, Oregon, with massive- 

 solid extrusion in its center. 



a central mass of crags, is here presented. The rim of the 

 crater, not appearing in the illustration, is composed mainly 

 of light-colored pumiceous lapilli, and is still intact for about 

 three-fourths of its original circumference, but its northern por- 

 tion is concealed, or more probably was breached and carried 

 away by a lava flow which was discharged from the crater 

 and went northward for a distance of two miles, and expanded 

 to a width of about one mile. All of the material extruded 

 seems to be andesite, which ranges in physical characteristics 

 from compact, dense, black volcanic glass or obsidian, to yellow- 

 ish-white pumice so light that it will float on water with the 

 buoyancy of cork. The lava stream has an excessively rough 

 surface, consisting of blocks of obsidian of all sizes up to eight or 

 ten or more feet in diameter with sharp edges and corners, 

 which form irregular piles and ridges in many instances fifty 



