THE BIRTH OF A VOLCANO 131 



Years ago it was a terrible blow to have my 

 theory shattered of a molten world, around which 

 stretched a tissue skin of soHd, cold rock on which 

 we dwell, like mealy-bugs on an apple. With such 

 a theory at one's beck it was so easy to picture the 

 volcanic lava as simply flowing up through open 

 pipes connected with this inner reservoir. But I 

 have come to find an equal thrill in the more logical 

 planetesimal idea, especially as it lessens in no way 

 the possible number and extent of volcanic out- 

 breaks in the future. 



I like to think of the incentive to these miles- 

 deep activities as residing at least in part in tidal 

 stresses, — in the same pull of the moon as that 

 which uncovers my tiny tide-pools. The great 

 craters of Mounts Whiton and Williams are quite 

 dead, choked apparently with solid plugs of lava 

 flows, but the major part of northern Albemarle 

 consists of the scoria, whose slow cooling, as I have 

 already said, allowed much of the retained gas to 

 escape, and left exposed the ploughed rock froth 

 over which we had to toil. The porous character 

 of this surface has precluded the blowing up of cra- 

 ters or ground in the present activity and has re- 

 sulted in the intrusive type of irruption which I 

 have described. The primary deep throat of lava 

 flow must exist high up on the shoulder slopes of 

 the two mountains, flowing thence beneath the 

 surface, finding actual peep holes for the hot lava 

 itself at scores of places, and sending forth the ex- 

 cess gases and steam through a thousand vents. 

 There was a nexus of at least twenty-five of these, 



