﻿CRYSTALLINE 
  ROCKS 
  OF 
  THE 
  ALPS. 
  93 
  

  

  then 
  (about 
  3^ 
  miles 
  below 
  Zell) 
  in 
  situ, 
  a 
  cleavage-foliation 
  being 
  the 
  

   dominant 
  structure. 
  Similar 
  rock 
  occurs 
  a 
  little 
  way 
  above 
  Zell, 
  

   where 
  it 
  is 
  evidently 
  greatly 
  affected 
  by 
  pressure. 
  In 
  the 
  upper 
  

   part 
  of 
  the 
  valley'around 
  and 
  above 
  Maierhof, 
  crystalline 
  limestone, 
  

   rather 
  compacter 
  in 
  structure 
  and 
  greyer 
  in 
  colour 
  than 
  that 
  south 
  

   of 
  the 
  central 
  watershed, 
  is 
  well 
  developed, 
  as, 
  for 
  instance, 
  at 
  the 
  

   Calvarienberg 
  below 
  the 
  village, 
  and 
  about 
  a 
  mile 
  and 
  a 
  half 
  above 
  

   it, 
  where 
  the 
  mass 
  crosses 
  the 
  valley, 
  and 
  extends, 
  according 
  to 
  Yon 
  

   Hauer, 
  far 
  away 
  eastwards 
  and 
  westwards. 
  Its 
  passage 
  into 
  calc- 
  

   mica-schist 
  and 
  then 
  into 
  normal 
  lead-coloured 
  " 
  Thonglimmerschiefer" 
  

   is 
  excellently 
  seen 
  in 
  a 
  knoll 
  on 
  the 
  left 
  bank 
  of 
  the 
  valley, 
  where 
  

   the 
  last 
  two, 
  like 
  that 
  already 
  described, 
  exhibit 
  a 
  distinct 
  stratifica- 
  

   tion-foliation 
  *. 
  The 
  crystalline 
  limestone 
  often 
  has 
  a 
  platy 
  struc- 
  

   ture, 
  which 
  strikes 
  not 
  far 
  from 
  E. 
  and 
  W., 
  varying 
  a 
  few 
  points 
  on 
  

   either 
  side. 
  In 
  one 
  place, 
  above 
  Haus, 
  we 
  see 
  it 
  almost 
  in 
  contact 
  

   with 
  a 
  coarse 
  gneiss 
  in 
  which 
  a 
  cleavage-foliation 
  is 
  very 
  strongly 
  

   marked, 
  and 
  of 
  which 
  the 
  last 
  outcrop 
  is 
  only 
  about 
  10 
  feet 
  from 
  

   the 
  last 
  knoll 
  of 
  limestone. 
  The 
  cleavage-structures 
  in 
  the 
  two 
  

   rocks 
  are 
  not 
  quite 
  parallel, 
  that 
  in 
  the 
  gneiss 
  being 
  slightly 
  S. 
  of 
  

   W., 
  that 
  in 
  the 
  limestone 
  a 
  little 
  N". 
  of 
  it. 
  At 
  this 
  point, 
  we 
  have 
  

   either 
  a 
  granite 
  intrusive 
  in 
  the 
  limestone 
  and 
  crushed 
  up 
  with 
  it, 
  

   or 
  a 
  natural 
  junction 
  of 
  an 
  older 
  and 
  a 
  newer 
  series 
  similarly 
  

   crushed, 
  or 
  a 
  faulted 
  junction 
  of 
  the 
  two 
  rocks. 
  As 
  the 
  limestone 
  

   here 
  is 
  exactly 
  in 
  the 
  same 
  crystalline 
  condition 
  as 
  it 
  is 
  in 
  the 
  three 
  

   other 
  localities 
  where 
  I 
  examined 
  it, 
  I 
  regard 
  the 
  first 
  hypothesis 
  as 
  

   inadmissible. 
  As 
  regards 
  the 
  third, 
  I 
  saw 
  nothing 
  to 
  suggest 
  excep- 
  

   tional 
  sliding 
  and 
  shearing, 
  but 
  only 
  direct 
  crushing. 
  Hence 
  I 
  do 
  

   not 
  think 
  there 
  has 
  been 
  an 
  overthrust-fault, 
  and 
  so 
  consider 
  it 
  on 
  the 
  

   whole 
  more 
  probable 
  that 
  limestone 
  and 
  other 
  members 
  of 
  the 
  

   " 
  Thonglimmerschiefer 
  " 
  series 
  were 
  deposited 
  upon 
  an 
  old 
  surface 
  of 
  

   the 
  gneiss. 
  It 
  is 
  true 
  there 
  is 
  no 
  sign 
  of 
  a 
  basal 
  conglomerate, 
  but 
  

   this 
  is 
  not 
  without 
  precedent. 
  

  

  Above 
  Maierhof 
  three 
  mountain-glens 
  pierce 
  deep 
  into 
  the 
  central 
  

   chain 
  of 
  the 
  Tyrol, 
  giving 
  the 
  traveller 
  another 
  opportunity 
  of 
  exa- 
  

   mining 
  the 
  " 
  Central 
  Gneiss 
  " 
  of 
  Yon 
  Hauer. 
  We 
  walked 
  several 
  

   miles 
  up 
  two 
  of 
  these, 
  the 
  Stillupthal 
  and 
  the 
  Floitenthal, 
  scruti- 
  

   nizing 
  the 
  rocks 
  in 
  situ, 
  the 
  screes 
  brought 
  down 
  by 
  lateral 
  torrents, 
  

   and 
  the 
  erratics 
  on 
  the 
  floor 
  of 
  the 
  glen. 
  In 
  the 
  Stillupthal 
  we 
  

   noted 
  a 
  porphyritic 
  gneiss, 
  with 
  occasional 
  darker 
  bands 
  of 
  lenticular 
  

   outline, 
  also 
  sundry 
  gneisses 
  and 
  mica-schists, 
  both 
  light 
  and 
  dark, 
  

   which 
  bore 
  some 
  resemblance 
  to 
  gneisses 
  of 
  the 
  Lepontine 
  type. 
  

   The 
  first-named 
  rocks 
  are 
  probably 
  of 
  igneous 
  origin, 
  the 
  difference 
  

   in 
  appearance 
  being 
  due 
  to 
  differences 
  in 
  the 
  effects 
  of 
  crushing. 
  

   Some 
  blocks 
  also 
  exhibited 
  junctions 
  which 
  suggested 
  an 
  intrusion 
  

   of 
  the 
  porphyritic 
  rock 
  into 
  the 
  " 
  Lepontine 
  " 
  gneiss, 
  anterior 
  to 
  the 
  

   crushing, 
  and 
  the 
  foldings 
  in 
  certain 
  of 
  the 
  schists 
  and 
  gneisses 
  are 
  

   such 
  as 
  would 
  be 
  most 
  naturally 
  explained 
  by 
  supposing 
  that 
  a 
  

   stratification- 
  foliation 
  existed 
  when 
  the 
  cleavage-foliation 
  was 
  pro- 
  

  

  * 
  For 
  the 
  microscopic 
  structure 
  of 
  the 
  rocks 
  of 
  this 
  district, 
  see 
  Appendix, 
  

   ■pp. 
  106-108. 
  

  

  