Yol.  49.] 
ST.  CASSIAN  STRATA  I1ST  SOUTHERN  TYROL. 
45 
ally  reappears  in  a  limited  variety,  during  the  Lower  Baibl  period, 
and  is  almost  entirely  absent  from  the  highest  or  ‘  Torer ’  zone  of 
Baibl  strata. 
Lower  & it.  Cassian  Zone. — Instead  of  the  continuous  stratified 
Cipit  Limestone  present  at  this  horizon  in  the  St.  Cassian  and 
Prelongei  district,  there  is,  at  several  places  farther  west,  a  charac¬ 
teristic  blocky  structure.  Large  blocks  and  masses  of  coralline 
Cipit  Limestone  are  embedded  in  ashy  strata ;  for  instance,  near 
the  higher  sources  of  the  Cipit  stream,  at  Mahlknecht,  below  Platt- 
kofl  on  the  Christiner  Ochsenwald,  on  Sella  Pass,  at  Yal  la  Sties,  at 
Cima  Pasni,  south  of  the  Pordoi  Pass,  and  again  in  the  lower  part 
of  the  Cortina  meadows.  Cidarid  spines  belonging  to  one  or  two 
species,  and  lithodendroid  corals,  are  the  only  fossils  which  I  found 
in  these  blocks  or  lenticular  beds  of  Cipit  Limestone. 
Middle  St.  Cassian  Zone. — In  all  cases,  the  marls  and  limestones 
immediately  succeeding  the  ‘  Cipit 9  horizon  contain  St.  Cassian 
fossils  of  the  ‘  Stuores  Wiese  ’  type.  The  Middle  St.  Cassian 
Beds  are  not  more  than  150-200  feet  thick  in  the  Mahlknecht  and 
PlattkofL  district,  and  the  ‘  blocky  structure  ’  recurs  at  several 
horizons.  The  dolomite-rock  of  Schlern  Mountain  and  Bosszahne 
succeeds  immediately  above  this  comparatively  slight  thickness  of 
St.  Cassian  Beds  on  the  north-eastern  side.  Farther  east,  the  St.  Cas¬ 
sian  Beds  become  thicker,  until  on  the  eastern  side  of  the  Sella 
massif  the  higher  and  very  fossiliferous  beds  of  Middle  St.  Cassian 
age  reach  their  first  complete  development  on  the  Prelongei  ridge, 
and  above  the  Pichthofen  Biff,  continuing  farther  in  the  Enneberg 
Yalley  (Abtey  slopes),  on  the  Yalparola  Pass,  and  in  the  Ealzarego 
Yalley  (west  of  Yerviers,  and  at  Bomerlo,  etc.). 
I  was  inclined  at  one  time  to  regard  the  fossiliferous  beds  exposed 
on  Forcella,  between  the  Bichthofen  Biff  and  Sett  Sass,  as  of  Upper 
St.  Cassian  age,  but  the  material  which  I  have  now  collected  here 
and  at  Stuores  does  not  justify  a  palaeontological  separation  of  the 
two  horizons.  The  fauna  on  Forcella,  excepting  one  new  species 
of  Omjphalophyllia ,  has  been  entirely  identified  with  the  St.  Cassian 
fauna  described  by  Munster  and  Laube.  At  the  same  time,  the 
absence  of  some  of  the  fossils  more  characteristic  of  lower  horizons 
on  Stuores  (e.  g.  Koninckina  Leonhardti ,  Wissm.),  and  the  presence 
in  greater  number  of  fossils  characteristic  of  higher  horizons  (e.  g. 
Avicula  Gea ,  d’Orb.,  Macrodon  strigilaturn ,  Must.,  sp.,  Anoplophora 
Munsteri ,  Wissm.),  mark  the  Forcella  beds  as  a  clearly  higher 
horizon  of  the  Middle  St.  Cassian  fauna. 
The  difficulty  of  attaining  a  positive  result  arises  from  the  fact 
that  the  fossils  from  Prelongei,  Stuores,  Sett  Sass,  Abtey,  and 
Heiligbreuz  could  not  be  kept  apart  in  the  literature,  for  the  fossil- 
collectors  of  the  district  mixed  them  all  together.  To  take  an 
example  from  the  appended  list  of  fossils  :  among  18  corals  occurring 
on  Forcella  di  Sett  Sass  6  are  identifiable  only  with  Middle  St. 
Cassian  (Stuores)  corals,  5  only  with  Upper  St.  Cassian  corals,  1 
with  both  Middle  and  Upper  St.  Cassian,  and  6  were  found  only 
