Cones in Halemaitnian. 



177 



diameter at the visible base. This had either stood or been constantly or intermit- 

 tently rising with its base certainly in contact with the molten lava apparently in its 

 hottest condition, and it had not melted, bnt, as it seems, had grown in size. I have 

 been on similar cones, as well as this and found the material much like the crust of 

 the crater floor, but here and there perforated with tunnels of irregular form and vari- 

 ous size. From the orifices thus formed came at all times hot vapor and often molten 

 lava, even at an elevation of half the height of the cone. It was unpleasant exploration, 





Fig. 107. HAI.KMAUMAU Al-'ThR THK DOWNFAI.I,. NOTK THK WONDERFUL NATURAL ARCH IN FOREGROUND. 



for the stifling sulphurous vapors had to be avoided as much as possible by keeping 

 on the windward side, and the things I wanted to examine were often on the lee side. The 

 foothold was of course insecure, but custom makes that tolerably easy to manage, and 

 the heat was generally not unbearable. My examination convinced me that the sub- 

 stance of the cones was the crust of the lake from which the cone rose. It was the 

 most refractory portion of the lava, and just here I must call attention to the need of a 

 laboratory right on the spot to determine the relative fusibility of the lavas found in 

 Kilauea; we know little enough of this problem, and more knowledge in this line would 

 not only explain beyond cavil the aa formation, but why these layers of cooled crust 

 should rise to such heights and not be melted again at the base. 



Memoirs B. P. B. Museum, Vol. II, No. 4.— 12. 1555 J 



