16 MTDDLEMISS: THE (OOLOGY OF U>AB STATE. 



numerous inclusions, but is much better developed ID another 

 specimen ( 3 2 8 5 5 > (12138) from Proia) from which it has been referred 



to zoisite. 



A specimen from the quarry on the railway just south of A lvau 

 (, 2 ^ , 12133 to 1-2135, PI. 8, fig. 3) is remarkable for the large amount of 

 biotite present and the general absence of quartz and felspar. The 

 calcite is as before and calls for no mention, the Lemberg staining 

 method revealing no dolomite. Diopside is father rare over much 

 of the rock, and there is a little scapolite in slides L2133 and 12134. 

 Rock No. 3 - 8 5 3 (12137. PI. 8, fig. 4), from the same locality, is similar, but 

 shows lines of cataclastic structure with bending of the calcite plates and 

 a finer granulation. There is also graphite in the rock. Another 

 specimen from the same quarry (££ 7 , L21 36) is represented in PI. 8, 

 ficr. 5. Its equidimensional granular character is beautifully shown. 



Another variety of the calc-gneiss is $& (12138) (12139, PI. 8, fig. 0), 

 from Proia village on the llarnav river. This rock is well banded in 

 pale and darker bands. The paler bands (12138) and indeed the whole 

 rock contains only a very small amount of calcite, the bulk being 

 composed of a finer grained aggregate of felspar and quartz, zoisite 

 in irregular areas or interrupted acicular parallel aggregates, large 

 irrermlarly bounded and frayed out plates of scapolite (meionite), 

 the usual diopside in grains sometimes showing crystal outlenes, 

 and sphene also in small lozenge-shaped grains. .Ml the minerals 

 are beautifully clear and fresh. The felspar and quartz form 

 a mosaic of grains scattered about and among the other con- 

 stituents. The zoisite is very characteristic, enabling one by analogy 

 to refer similar mineral occurrences in other specimens of the calc- 

 gneiss (see 3 v\, ante). Besides its high refractive index and weak 

 double refraction giving abnormal interference tints of a rich violet 

 ^rey, its extinctions parallel to the elongated prisms and its biaxial 

 figure in convergent light all point unmistakably to zoisite, a con- 

 clusion also borne out by the general habit and appearance of the 

 mineral. It is developed in considerable quantity in discontinuous 

 plates and more or less regularly oriented acicular prisms in the 

 quartz-felspar mosaic. The large meionite plates arc not bounded 

 by crystal faces but by a perfectly irregular wandering edge. The 

 low index oi refraction and strong birefringence (about 035, working 

 from that of the known diopside) of this mineral is in great contrast 

 to the zoisite. The cleavage, presumed to be parallel to a (100) 

 is well seen by parallel cracks in many examples which all give 



