Yol.  49.]  8T.  CASSIAS  8TEATA  IX  SOUTHERN  TYROL.  75 
(Muschelkalk),  occurred  at  a  considerable  height  above  the  Toblach 
Valley  in  the  Sari  Bach  ravine  ;  it  also  occurs  in  the  dolomite  on 
both  sides  of  the  valley  nearly  as  far  south  as  the  bridge  below 
the  Flodiger  Wiese.  On  the  other  hand,  the  ascent  to  that  Wiese 
cuts  through  a  dolomite  which  is  unquestionably  Schlern  Dolomite, 
often  possessing  the  oolitic  structure  characteristic  also  of  the 
Wetterstein  Kalk  in  Northern  Tyrol.  I  concluded  that  Schlern 
Dolomite  rests  on  Mendola  Dolomite  at  Xockboden,  although  an 
exact  limiting-line  can  naturally  not  be  drawn. 
Assuming  that  the  Sari  Kofele  and  Kasamiitz  dolomite-rock  is 
Mendola  Dolomite,  the  St.  Cassian  Beds  of  the  Flodiger  Wiese  rest 
on  the  last-named  horizon.  They  dip  below  the  Schlern  Dolomite  of 
the  Diirrenstein,  and  on  the  western  slopes  of  that  mountain,  towards 
Stolla,  rest  conformably  upon  Wengen  strata.  We  have,  between 
the  Flodiger  Wiese  and  the  Diirrenstein,  a  fault-plane  hading  gently 
to  the  south,  on  which  a  system  of  Upper  Trias  has  been  thrust 
down  upon  a  system  of  Lower  Trias.  A  thrust  of  that  kind  explains 
the  apparent  unconformity  of  the  St.  Cassian  Beds  and  the  Schlern 
Dolomite  upon  the  Mendola  Dolomite. 
The  north-and-south  vertical  fault,  which  separates  the  system 
of  strata  exposed  on  the  Sari  Alp  and  Kasamiitz  from  that  of 
the  Toblach  Valley,  is  of  later  date,  and  cuts  through  the  thrust- 
plane.  This  fault  lets  down  the  Schlern  Dolomite  and  Mendola 
Dolomite  which  form  the  Nockboden  system.  On  the  western 
side  the  thrust-plane  system  is  cut  off  at  Kirchenschroffen  by  the 
continuation  of  the  north-and-south  fault  between  Lung  Kofi  and 
the  Kameriod  Wiesen.  It  may  be  that  there  is  a  farther  extension 
east  and  west  of  this  thrust-plane,  and  in  the  subsequent  changes 
brought  about  by  vertical  faulting  we  may  have  an  explanation 
of  the  various  anomalies  in  the  neighbouring  regions. 
In  the  four  sections  10-13  (pp.  34,  35)  I  have  shown  the  result 
of  my  observations  at  the  Diirrenstein,  and  can  only  regret  that 
time  did  not  allow  of  my  continuing  the  study  of  the  geology  farther 
west.  With  the  same  inclination  and  throw  of  the  thrust,  Dachstein 
Dolomite  and  Baibl  strata  of  the  upper  system  would  rest  on 
Schlern  Dolomite  of  the  lower  ;  but  I  need  not  enter  into  con¬ 
siderations  which  do  not  immediately  concern  the  district  mapped. 
I  have  already  indicated,  in  my  preliminary  remarks  (p.  60)  on  the 
district  between  the  northern  outer  zone  and  the  Falzarego  Valley, 
the  general  tectonic  features,  as  I  should  interpret  them  after 
detailed  study  of  some  portions. 
The  tectonic  relations  of  the  Diirrenstein  massif  are  simple.  It 
is  separated  from  the  4  Dachstein  ’  region  by  a  main  north-and- 
south  line  of  fault,  continued  also  across  the  Ampezzo  Valley  at 
Schluderbach. 
The  road  between  Alt  Prags  and  Schluderbach  bends  eastward 
at  Briickele,  and  winds  round  the  base  of  the  Dachstein  massif  of 
Bauhe  Gaisl  on  the  right.  Wrengen  and  St.  Cassian  strata  are  in 
place  on  the  left,  with  an  east-and-west  strike  and  a  slight  southerly 
