MAGMATIC DIFFERENTIATION OF IGNEOUS ROCKS 531 
a little Al,O;, we find that the dunites consist nearly exclusively 
of olivine, and the saxonites usually of predominant olivine with 
only quite little bronzite or enstatite-bronzite. 
Olivine-bronzite (or enstatite) rocks with predominant ortho- 
pyroxene and quite little olivine are very rare, and personally I have 
only once (1893) found such a rock, viz.,as a local facies of aperidotite 
at Esjeholmen near Nes6, in the Hestmandé district, near the Polar 
Circle in the northern part of Norway.' 
As illustrated in Figure 26, there here appear rosettes of radially 
arranged bars of enstatite which in most places are entirely un- 
changed, but in’some places somewhat altered to tremolite, clino- 
chlorite, talc, and magnesite. 
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Fic. 26.—Enstatite-olivine rock from Esjeholmen, near Nesé, Hestmandé dis- 
trict, northern Norway. Contains great rosettes of enstatite and an intervening 
mass of olivine with some enstatite. (1/r1o nat. size.) 
The bars of enstatite in these rosettes may reach a length of 
1 dm., or somewhat more, and the enstatite rosettes may have the 
size of the head of a full-grown man. The intervening mass between 
the enstatite rosettes consists of olivine and enstatite. In the 
entire rock we may reckon about 80 per cent enstatite rosettes 
and only about 20 per cent intervening mass, consequently for the 
whole rock about oo per cent enstatite and to per cent olivine, in 
addition to a minimal quantity of chromite. I cannot explain 
this structure otherwise than that at first the enstatite of the large 
rosettes was formed, and later the intervening mass, consisting of 
olivine and enstatite. The result of this is that the sequence of 
t See a treatise by myself in Zeztschr. f. prakt. Geol., 1894, pp. 389-92, and a 
treatise by C. W. Carstens, ‘‘ Norske peridotiter,”’ I, Norsk geol. tidskr., Vol. V (10918). 
