322 B. K. Emerson — Cylinders of Scoriaceous Diabase. 



As a line of bubbles escapes upward from a porous body sub- 

 merged in water, columns of such bubbles may have risen 

 from such an enclosure as the above, boring holes in the viscid 

 mass and these might be filled by the porous trap. I have seen 

 empty parallel holes on the surface of the trap 1/2 inch wide 

 and 4 inches deep at Titan's Piazza in the Holyoke Range. 



Fig. 1. 



I have also seen at Kilauea a hollow tube in the lava 4-5 

 inches in diameter and perhaps a foot deep where the liquid 

 lava had surrounded a small tree and became solid so quickly 

 that the trunk on burning or rotting left a cylindrical cavity. A 

 second scoriaceous flow might have filled this hole and made a 

 result like that here described. That is, however, a rather far- 

 fetched explanation, especially as the trap in the block adjacent 

 to the tubes is of the same texture as farther away from these 

 tubes. 



Amherst, Mass. 



