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C. B. Dutton—Hawaiian Volcanoes. 223 
at the summit immediately sealed up, being tapped, I presume, 
by the outbreaks which occurred at a considerably lower level. 
lavas of both Kilauea and Mauna Loa seem to me to 
be of an abnormal type. The analyses are not yet made and 
I can therefore give only their superficial character. They 
have the appearance of being extremely basic, decidedly more 
so than normal basalts. I cannot help thinking that they may 
be fairly relegated to what Judd describes as ultra basalts. 
Most of the lavas of Mauna Loa contain excessive quantities 
of olivine, many specimens being at least half composed of that 
mineral. The lavas of Kilauea, on the other hand, whether in 
the pit itself or in the country round about, seldom show much 
olivine. But the eruption of 1840, which belongs physically to 
the Kilauea group, is highly olivinitic, while the last eruption 
of Mauna Loa shows little or no olivine. Iam led to suspect 
that the ultimate analyses of the two lavas, whether olivinitic 
or not, will show but little difference. In other words, I sus- 
ducts upon Mauna Loa and their great abundance on Mauna 
ea. The latter mountain is covered all over with magnificent 
the leeward side they are far less extensive, but are by no 
means wanting. During the past few years my attention has 
frequently been called to the very great inequalities of effects 
produced upon the same mass by varying degrees of energy 1n 
the agencies of degradation. Nowhere does it come out more 
clearly than in these islands. The windward sides in most 
cases Neve been devastated to an astonishing degree, so much 
so that { sometimes shrink from the task of trying to convince 
anybody of the reality which I am sure of. But on the lee- 
