4  MISS  OGII/v IE  ON  THE  WENGEN  AND  [Feb.  1 893, 
appear  again  at  the  higher  horizon  of  the  Baibl  Beds,  together 
with  a  certain  number  belonging  to  a  distinct  ‘  Baibl  ’  fauna. 
The  Wetterstein  Kalk  in  some  places,  however,  lies  directly  upon 
the  Wuschelkalk,  no  Partnach  strata  being  developed  ;  and  in  its 
eastern  and  western  extension  the  Wetterstein  Kalk  thins  out.  In 
Eastern  Tyrol  its  place  is  taken  by  the  Hallstadt  Limestone,1  while 
in  the  west  the  Baibl  Beds  lie  conformably  on  the  Partnach  Beds. 
The  various  opinions  which  have  been  held  regarding  the  pro¬ 
bable  representative  in  Northern  Tyrol  of  the  St.  Cassian  strata  of 
Southern  Tyrol  will  be  stated  below  in  the  review  of  the  special 
literature.  “  Suffice  it  to  say  that  the  name  of  4  St  Cassian  strata  ’ 
has  now  no  value  as  indicating  a  sure  horizon  in  the  series  of 
Alpine  Upper  Trias  ;  at  most  it  has  retained  clear  association  with 
the  fauna  found  in  the  immediate  neighbourhood  of  St.  Cassian. 
II.  Previous  Discovery  and  Speculation  regarding  the  Upper 
Triassic  Strata  in  the  Tyrol  (with  special  reference  to  the 
St.  Cassian  Beds  in  Southern  Tyrol). 
At  a  time  when  the  historical  geology  of  the  British  Isles,  F ranee, 
and  Germany  had  been  firmly  based  on  the  careful  and  comparative 
studies  of  geologists  in  those  countries,  the  elements  of  Alpine 
geology  were  scarcely  understood.  Those  immense  masses  of  lime¬ 
stone  and  dolomite  which  characterize  the  northern  and  southern 
zones  of  the  Alps  seemed  without  parallel  elsewhere  in  Europe. 
As  the  limestone-rocks  have  outwardly  much  similarity,  and  the 
few  fossils  which  they  contain  were  for  a  long  time  unknown,  the 
older  writers  believed  them  to  belong  to  one  and  the  same  forma¬ 
tion,  and  grouped  them  conveniently  together  under  the  title  of 
4  Alpenkalk.’  There  are,  however,  here  and  there  amidst  the 
wonderful  rock-scenery  of  the  Tyrolese  Alps,  high-lying  stretches  of 
green  meadow  and  *Alm.’2  Gradually  geologists  carried  their 
researches  into  these  remote  4  Alpen,’  and  found  the  marls  and 
shales  to  be,  in  many  cases,  fossiliferous.  Fossils  were  collected 
and  examined,  and  it  became  evident  that  the  fauna  occurring  in 
the  Alpine  mountains  of  the  Tyrol  had  a  character  quite  different 
from  that  of  any  fossil  fauna  up  to  that  time  known  in  other  parts 
of  Europe. 
It  was  on  such  high  mountain-meadows  that  the  Avicula  con- 
torta- zone  was  traced  in  Northern  Tyrol  soon  after  Leopold  von 
Buch’s  3  first  discovery  of  the  characteristic  fossils  at  Hirschberg. 
1  The  Hallstadter  Falk  belongs  to  the  development  of  Trias  in  the 
‘  Jurassic  Province’  recognized  by  Mojsisovic3,  whereas  Wetterstein  Kalk  occurs 
in  the  ‘Mediterranean  Province’  (this  embraces  the  Western  ana  Southern 
Alps).  Mojsisovics  also  distinguishes  a  Lower  Keuper  division  of  the  Alpine 
Trias,  the  ‘  Noric  zone,’  including  the  strata  from  the  Upper  Muschelkalk  to  the 
Baibl  Beds,  and  an  upper  division,  the  ‘  Karnic  zone.’ 
2  Aim  or  Alp  is  the  German  word  for  pasture-land  in  the  mountains,  where 
cattle  remain  the  whole  summer  through  in  the  open  air.  In  Southern  Tyro 
hay  is  often  grown  and  gathered  into  small  huts,  Alpenhutten,  and  foi  t  ie 
convenience  of  herd-bovs  empty  huts  are  left,  the  so-called  Kochhutten.  T  ese j 
huts  help  much  in  reading  the  maps,  as  they  are  always  marked. 
3  ‘  Schichten  mit  Avicula  ....,’  Abh.  d.  k.  Akad.  Berlin,  1828,  p.  84. 
