PIED3I0XTITE- SCHIST IX JAPAX. 



479 



In this schist we find a peculiar epidote in the form of long irregular 

 plates (|— 1 centim.), having a slight yellowish-green colour. and being 

 irregularly traversed by transverse cracks and longitudinal strias. 

 The morphological habitus differs from that of an ordinary epidote 

 in its more flattened tabular condition. It possesses sometimes a 

 faint rosy tint, its pleochroism is weak, but distinct, being more in- 

 tense when the short diagonal of the lower nicol is at right angles 

 to the longer sides of the epidote. In other instances the red pig- 

 ment is localized in the centre (fig. 4). so as to form a distinct zone ; 



Fig. 4. 



A 



but the reversed case, i. e. a red margin with the yellow centre, has, 

 within the writer's knowledge, never yet been observed. 



The rosy pigment which characterizes this epidote is certainly 

 due to the presence of a manganese oxide, and the mineral forms an 

 intermediate link between common epidote and piedmontite. One 

 point in connexion with this epidote should not pass unnoticed, 

 namely the abundant enclosures of aggregates of opaque iron-glance, 

 and blood-red hexagonal scales of the same mineral, since the typical 

 piedmontite is entirely free from enclosures of such a kind. This 

 indicates the fact that the latter (piedmontite) has crystallized out 

 before the yellowish-green epidote. 



(e) Garnet. — In the glaucophane-schist from Otakisan. in the 

 Island of Sikoku, we find a large number of rhombic dodecahedra 

 (size of a pea) of a greenish-yellow garnet. A slide cut from one 

 of these garnets shows, under the microscope, that it is made up of 

 different minerals as indicated in figure 5. This crystal is, indeed, a 

 small mineral cabinet of all the constituents of the rock in which it 

 occurs, except glaucophane. The violet piedmontite needles, clumps 

 of dark iron-glance, hexagonal scales of iron-glance, the knee-shaped 

 twins of rutile-needles which contain in their substance also a large 

 number of already twinned crystals upon Px , and, lastlv. highlv 



2i2" 



