436 I ES VOGM 
In the norites and gabbros, especially rich in orthorhombic 
or in monoclinic pyroxene (hypersthene-norites and diallage- 
gabbros) with relatively little, say 10, 20, or 25 per cent of labra- 
dorite, the pyroxene individuals to a very great extent show an 
idiomorphic contour against the plagioclase. Further, the pyroxene 
individuals are often to some extent accumulated in aggregates, 
consequently showing synneusis structure. On the other hand, 
the plagioclase shows no signs of idiomorphism but only appears as 
ery 
Fic. 11.—Photomicrograph (18:1) Fic. 12.—Drawing (11:1) 
Norite from Meseel, Norway. Hypersthene with spredominant idiomorphic 
outlines against the labradorite. The photograph represents the lower part of the 
drawing. The shaded mineral in small quantity is hornblende, the black pyrrhotite. 
mesostasis (Zwischenklemmungsmasse) between the pyroxene indi- 
viduals. This may be explained by the fact that an essential part 
of the orthorhombic or monocline pyroxene in question had solidified 
even before the commencement of the crystallization of the plagio- 
clase. We must not draw the conclusion, however, that the 
pyroxene individuals in their entirety had crystallized at an earlier 
stage than the plagioclase. On the contrary, in some of the 
pyroxene individuals, we find the idiomorphic contour against the 
plagioclase lacking, and this must indicate a simultaneous crystalli- 
zation of both minerals during the last stage of the solidification. 
As an example we refer to the photograph (enlarged 18:1) and 
