565 
Margin: plagioclase with little green amphibole, ore, and light- 
brown glass without microlites. 
5. xenolith with concentration of the dark constituents in the 
central parts, i.e. 
Central part: almost exclusively brownish green amphibole with 
a margin of ore and very little plagioclase. 
Margin: much brownish green, amphibole with angular forms 
and rim of ore, plagioclase with more or less idiomorphic form, 
“magnetite and very little augite and hypersthene. 
6. plagioclase, much olivine, little hypersthene and brownish-green 
amphibole. 
7. plagioclase, brown, almost entirely resorbed amphibole and 
little glass. 
Phenomena of resorption. 
a. of olivine. There are numerous xenoliths, in which the olivine 
is quite fresh, without resorption rim, e.g. in olivine-rich xenoliths, 
which contain besides plagioclase and rather much glass, only little 
brownish-green amphibole and some hypersthene. Here the line of 
demarcation between plagioclase and olivine is generally very sharp, 
but sometimes we observe the brownish-green amphibole disposed 
round the olivine or a combination of small amphibole crystals and 
a mixture rich in glass, of which the latter also occurs sparingly 
among the chief constituents, intrudes into the olivine crystals. 
The amphibole is no doubt one of the last erystallization-products, 
and it may be that, before its formation, a slight resorption of the 
olivine has taken place, which however occurs only locally and can 
be brought about only by a small amount of residual magma. 
Pronounced resorption-phenomena are shown e.g. by the olivine 
of xenoliths in blocks which were thrown out during the eruption 
of 1914, and are now overlying the lava-flow of 1904. The boundary- 
line between plagioclase and olivine is nowhere sharp here, but the 
remainders of the olivine-crystals are encompassed by a zone of 
resorption against which the plagioclase is bordered in a curving 
and undefined way. Sometimes the original olivine has completely 
disappeared; it has been replaced by a mineral-aggregate, chiefly 
made up of hypersthene. If the olivine-erystals have been preserved 
in part, they are seen to be encompassed by a margin, in which 
a concentric structure can be established. Close to the olivine the 
margin mostly consists only of an aggregate of larger hypersthene- 
crystals, by the side of which there may occur a little augite. 
