116 
BAVARIAN BASALTS 
stituents. The augites growing in the former granite lose their 
brown color and change to green. They are then larger and bet¬ 
ter bounded. It is even possible to isolate crystals altogether 
similar to diopside, showing the faces (110), (010), (100) and 
(111). These crystals are visible under the microscope as though 
swimming in sanidine, which is abundant in all of these meta¬ 
morphosed granites. Besides the diopside, there are, in all the 
inclusions, aegirine and catophorite (a yellowish-brown soda horn¬ 
blende). Both, pyroxene and hornblende, are found not only in 
independent crystals, but also intergrown zonally. 
Sandstone fragments in some basalts contain nearly the same 
minerals as the granite inclusions and a similarly metamorphosed 
zone surrounds them. But, generally, such fragments are fritted, 
and if the the sandstone was rather clayey, it is changed to basalt- 
jasper. Remnants of quartz and occasionally of feldspar are to 
be found in this partly fused matter, as are also new minerals, 
cordierite, spinel, and sillimanite. 
Besides these inclusions of altered rocks, there are also found 
in the basalts many small cavities filled with various minerals. As 
being of more consequence than others, there may be mentioned 
the two zeolites, natrolite and phillipsite. Both deviate, more or 
less, in their optical properties, from all other known occurrences 
of this kind. Moreover, just as the basalt in the immediate vicin¬ 
ity of an inclusion is different from ordinary basalt, so, also, are 
the walls of these cavities composed of an altered basalt. How¬ 
ever, the crystals of diopside are not encompassed by sanidine but 
by zeolite. Towards the center of the cavity are the well bounded 
crystals of natrolite and phillipsite. From the close association 
of the zeolites and the augite of the basalt, it may be concluded 
that the crystallization of the zeolites must have begun even as 
early as the pneumatolitic period of the basalt’s solidification. 
Frequently there is found in the basalt cavities and in cavities 
of the inclusion, a greenish mineral, having a hardness between 
that of gypsum and rock-salt. The structure is that of a colloid 
— sometimes amorphous, sometimes spherulitic. In the latter 
case, the fibres show double refraction. The appearance is quite 
similar to that of cerolite, but it is impossible to identify it, either 
with this, or with any other, known mineral on account of its 
chemical composition. According to the quantitative analysis, it is 
