95 
Vol.  49.]  4  GREENSTONES,’  ETC.,  EROM  THE  PENNINE  ALPS. 
according  to  the  legend,1  Gruner  Schiefer,  Horriblen cl e-S chief 'er,  and 
Serpentine  ;  on  the  eastern  all  the  green  rocks  are  coloured  as  serpen¬ 
tine.  In  the  former  case  this  term  is  correctly  employed,  so  far  as  my 
knowledge  goes,  but  in  the  latter  it  has  scarcely  any  petrological  value. 
Borne  patches  of  serpentine  undoubtedly  occur  in  the  tract  thus 
coloured,  but  there  is  also  a  little  gabbro  2  (including  the  well-known 
smaragdite-euphotide  of  the  Saasthal),  and  the  predominant  rock  is  a 
schist,  generally  hard,  which  consists  mainly  of  hornblende,  chlorite 
(or  altered  biotite),  with  more  or  less  epidote,  garnet,  felspar, 
quartz,  etc. — in  short,  it  is  the  Hornblende- Schiefer  or  the  Gruner 
Schiefer  of  the  Zermatt  district,  generally  corresponding  more 
nearly  with  the  former.3  The  relations  of  this  rock  to  the  other 
crystalline  schists  of  the  district  are  not  easily  determined. 
Evidently  it  is  in  close  connexion  with  the  calcareous  and  other 
associated  schists  ( Graue  Schiefer ,  Tcalkhaltig ,  of  the  map),  but  dykes 
occur  in  the  latter  near  to  the  boundary  of  the  two  masses,  which 
seem  like  offshoots  from  the  former,  and  so  suggest  an  intrusive 
origin.4 5 
That  the  region  as  a  whole  has  been  affected  by  great  pressure — 
perhaps  on  more  than  one  occasion — cannot  be  doubted.  The  calc- 
schist  group  is  folded  up  with  the  gneisses  ;  all  alike  exhibit  dis¬ 
tinctive  signs  of  a  cleavage-foliation,  produced  by  movements 
posterior  to  the  stratification-foliation,0  whatever  may  have  been 
the  cause  of  the  latter.  Immense  masses  of  rock  have  been 
removed  by  denudation.  Here  and  there,  sometimes  in  isolated 
spots  among  the  peaks  and  glaciers,  we  come  upon  fragmentary 
infolds  of  the  calc-schist  group.  These,  within  no  great  distance 
of  Saas  Eee,  differ  in  elevation  above  sea-level  by  about  7000  feet ; 
from  the  immediate  neighbourhood  of  the  hamlet  they  can  be  seen 
cropping  out  on  the  mountain -slopes  through  full  half  that  range. 
They  are  cut  by  the  serpentine  and  by  a  granite,  as  a  rule  coarsely 
porphyritic,  as  well  as  by  the  ‘  greenstone  ’-dykes,  which  have  been 
more  or  less  modified  by  pressure. 
Of  these  schistose  4  greenstones  ’  the  first  to  be  described  was  found 
on  the  eastern  flank  of  the  peak  of  the  Mittaghorn  (10,328  feet)  at 
a  height  probably  of  about  9600  feet  above  the  sea.  It  forms  a 
lenticular  mass  about  half  a  yard  wide  and  from  2  to  3  yards  long,6 
completely  included  in  the  calc-schist,  the  micaceous  bands  in  which, 
indicative,  I  presume,  of  an  original  stratification,  sweep  round  it 
1  Sheet  XXIII.  of  the  ‘  Geologische  Karte  der  Schweiz.’ 
2  Distinguished  by  another  colour  on  Sheet  XXII. 
3  So  far  as  I  know  these  rocks,  the  names  designate  somewhat  different  types, 
the  former  being  rather  the  coarser  and  more  obviously  hornblendic,  the  latter 
the  more  ‘  slaty  ’  looking,  but  I  believe  them  to  be  really  closely  related.  On 
Sheet  XXII.  only  one  colour  is  used. 
4  On  the  Mittaghorn  the  evidence  of  intrusion  into  the  gneiss  seems  very 
strong. 
5  The  terms  are  used  in  the  senses  proposed  by  the  writer,  Quart.  Journ. 
Geol.  Soc.  vol.  xlii.  (1886)  Proc.  p.  64. 
6  Debris  masked  the  lower  end ;  about  2  yards  was  exposed,  and  in  little  more 
than  a  yard  the  calc-schist  formed  a  continuous  mass. 
