Vol.  49.]  CRYSTALLINE  SCHISTS  OF  THE  MALVERN  HILLS. 
409 
in  the  same  crystalline  form,  the  chlorite  being  regularly  inter- 
grown  in  repeated  laminae  parallel  to  the  basal  plane  of  the  mica. 
Some  of  the  mica  occurs  in  irregular  patches  elongated  in  the 
direction  of  the  schistosity,  and  it  is  this  kind  which  graduates  into 
the  chlorite.  Sometimes  the  mica  is  in  such  minute  microliths,  and 
is  so  intimately  mixed  up  with  the  granules  of  quartz-felspar,  that  a 
graphic  representation  of  the  facts  is  impossible. 
Fig.  3  (Slide  486). 
Intermediate  between  the  diorite  and  the  schist.  The  lightly -shaded  parts 
are  ‘  quartz-felspar  ’  and  white  mica  ;  the  darker  patches  are  brown  mica 
and  chlorite.  Some  of  the  chlorite  is  intergrown  with  the  white  mica. 
A  fracture  in  the  rock  passes  across  the  slide.  Some  traces  of  shear- 
planes  are  accentuated  by  opaque  matter. 
The  changes  seen  in  the  quartz-felspar  are  very  instructive.  The 
outlines  have  become  more  rounded,  and  there  is  a  general  elonga¬ 
tion  in  the  direction  of  foliation,  so  that  fusiform  shapes  are  common. 
The  mosaic  structure  is  more  frequent,  and  none  but  the  smallest  par¬ 
ticles  polarize  as  a  unity.  In  the  secondary  consolidation,  the  mica 
and  chlorite  are  the  first  formed,  and  the  quartz-felspar  is  moulded 
upon  their  contours. 
The  rock  here  described  is  a  true  crystalline  schist,  as  seen  in  the 
parallelism  of  the  minerals,  the  absence  of  clastic  structure,  the 
granulation  of  the  quartz-felspar,  and  the  crystalline  condition  of 
all  the  constituents. 
Here  and  there  in  the  band  of  the  schist,  specimens  (No.  347, 
fig.  4,  p.  411)  may  be  obtained  in  which  the  metamorphism  has  pro¬ 
ceeded  still  farther.  The  chlorite  has  almost  disappeared,  and 
the  rock  mainly  consists  of  lenticular  or  linear  mosaics  of  quartz- 
felspar  enclosed  in  a  meshwork  of  fibrous  white  mica,  which 
Q.  I.  G.  S.  No.  195.  2  e 
