22 
STISS  OGILVIE  OH  THE  WEHGEN  AND 
[Feb. 1893, 
This  horizon  is  further  accentuated  by  a  sheet  of  augite-porphyry 
in  the  fossiliferous  marls  and  limestones  immediately  above  the  Cipit 
Limestone,  and  the  subsequent  intermixture  of  ashy  rock  with  the 
ordinary  marine  sediments.  The  fossils  in  the  ashy  rocks  are 
few  and  fragmentary,  but  passing  upward  they  increase  in  number 
and  variety,  until  in  the  beds  on  the  Prelongei  ridge  the  St.  Cassian 
fauna  as  such  reaches  its  highest  point. 
As  appears  from  Section  3,  a  higher  series  of  fossiliferous  marls 
and  shaly  limestones  succeeds,  in  which  thick  beds  of  limestone 
and  a  dolomitic  rock  thin  out.  The  limestone-rock  has  been  called 
4  Cipit  Xalk,’  and  indeed  it  looks  exactly  like  the  Cipit  Limestone 
of  the  lower  horizon.  Nevertheless,  it  is  no  constant  bed  at  this 
horizon ;  the  beds  above  and  below  have  the  same  characters  and 
the  same  fauna,  whereas  the  Cipit  Limestone  group  at  the  lower 
horizon  has  both  a  stratigraphical  and  palaeontological  value.  Above 
this,  the  highest  fossiliferous  series,  the  rock  is  entirely  dolomitic. 
For  palaeontological  reasons  which  are  explained  below,  I  have 
grouped  the  whole  series  of  strata  between  the  Lower  St.  Cassian 
zone  and  the  Schlern-Dolomite  rock  of  Sett  Sass  as  the  ‘Middle 
St.  Cassian  ’  or  ‘  Stuores  ?  zone ;  farther  east,  a  higher  palaeontolo¬ 
gical  horizon  succeeds  above  the  ‘  Stuores  ’  zone  and  below  the 
Schlern  Dolomite.  In  collecting  the  fossils  in  the  St.  Cassian 
district  I  was  very  careful  to  keep  separate  these  of  the  Forcella 
di  Sett  Sass  from  those  of  Prelongei  and  Stuores  meadows,  the 
‘  Forcella’  zone  having  been  more  than  once  referred  to  Raibl  age. 
Local  Development  and  Exposure. 
''The  ‘  heteropic ’  strata  of  the  Richthofen  Riff  and 
Castello  conformably  underlying  t  he  Schlern  Dolomite. 
Pauna :  see  List  of  Fossils  found  on  Forcella  di  Sett 
Sass. 
The  series  of  fossiliferous  beds  on  the  Prelongei 
ridge. 
1  The  less  fossiliferous  ashy  beds  forming  the  main 
mass  of  the  strata  on  Stuores,  Piccol,  Ruones  and 
Corte  slopes. 
Fauna :  see  List  of  Fossils,  pp.  48  et  seqq .,  under 
‘  Stuores  ’  (Prelongei,  Stuores,  Piccol,  Ruones 
and  Corte  slopes  included). 
^Hard  thickly-bedded  limestone,  sometimes  forming 
massive  rock — occurring  as  a  firm  band  throughout 
the  lower  level  of  the  slopes  mentioned  above. 
Fauna :  pre-eminently  that  of  a  reef-limestone, 
including :  Cidaris  dorsata,  C.  Eoemeri ;  Encrinus 
cassiqnus,  Dentacrinus  jpropinquus ;  Thamnastrcea 
Zitteli. 
The  best  exposures  of  Wengen  Peds  occur  on  Monte  Sief  and 
near  Corvara ;  and,  comparing  these,  a  lower  series,  in  which  sedi¬ 
mentary  tuffs,  ashy  grits,  and  Hcilobia 1  Lommeli-shales  predominate, 
1  [In  a  recent  publication — ‘  Die  Perm-  Trias- und  Jura-Formation  auf  Timor 
und  Rotti’  (Palasontographica,  vol.  xxxix.  Aug.  1892),  Dr.  A.  Rothpletz  has 
shown  (pp.  91-96)  that  the  differences  hitherto  recognized  between  Daonella 
and  Halobia  are  not  of  generic  value;  the  older  name  of  Halobia  is  therefore 
used  throughout  the  present  paper.] 
Middle 
St.  Cassian  Beds. 
Lower 
St.  Cassian  Beds. 
