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groundmass of the lava of the dome and the devitrified glass of 
the xenoliths have then crystallized almost simultaneously. 
The xenoliths mentioned sub 2 do not differ much from those just 
described; they are all characterized by a small amount of pyroxene, 
while also a small amount of olivine was found in some. The 
amphiboles show a narrow resorption rim, which contains much 
ore, mixed: with pyroxene (principally augite). 
Veins. of the same composition as the resorption rim are found 
in.the more central part of the crystals, which are larger than those 
of the other minerals, which present an irregular outline and may 
enclose all the other components entirely or partly, also olivine, 
if it oceurs in the xenoliths. The olivine presents rounded shapes 
without distinct crystal faces and has been altered to some degree 
into a brownish red or black substance, rich in iron. The glass-bearing 
mass is rich in laths of plagioclase and also contains many pyroxene- 
microlites. The glass is very dark and the devitrified portion is 
apparently rich in iron; ore hardly shows itself in separate grains. 
The xenoliths with more pyroxene, mentioned sub 3 (Pl. fig. 3) 
are distinguished from the preceding chiefly by the decrease of the 
amount of amphibole and the increase of pyroxene. Various structures 
occur. Pyroxene (augite as well as hypersthene) occurs occasionally 
with a few larger amphibole-, and plagioclase-crystals in a finer 
crystalline mixture, consisting mainly of plagioclase with little 
pyroxene. The pyroxene (above all the augite) then exhibits similar 
skeleton-like structures to those of the amphibole, and then incloses, 
just like the last-named mineral, numerous plagioclase crystals, which 
also penetrate into the augites with idiomorphous erystal form, so 
that these are one of the last crystallisation products of the xenolith. 
In connection with this the smaller plagioclases are entirely free 
from enclosed dark minerals, the larger nearly so. It is these 
xenoliths that contain olivine with rounded sbapes and mostly 
enclosed by the amphibole. Devitrified glass occurs in small quantity. 
In other xenoliths also bearing occasionally olivine, for the rest 
little different from the others, the pyroxenes are chiefly restricted 
to the fine-erystalline bulk of the xenolith, while only few larger 
crystals occur with some of partly resorbed amphibole and of 
plagioclase. A portion of the xenoliths of this group displays the 
normal, medium grained structure without larger crystals; here we 
find evidence of the posterior crystallization of the amphiboles, 
because they occur in skeleton shaped crystals, which occasionally 
enclose the pyroxene. The different stages of resorption of the 
amphibole, mentioned already for the xenoliths described sub 1, 
