Yol.  49.]  ST.  CASSIAS’  STRATA  IN  SOUTHERN  TYROL.  47 
of  St.  Cassian  strata  are  present ;  the  typical  Stuores  or  Middle 
St.  Cassian  zone  is  first  completely  developed  in  Enneberg,  while 
above  it  there  succeeds,  at  Cortina,  Misurina,  and  the  Seeland  Alpe, 
a  fossiliferous  Upper  St.  Cassian  zone. 
In  the  wide  district  north  of  Ealzarego  and  Ampezzo  Valleys,  where 
St.  Cassian  strata  are  not  exposed,  their  non-occurrence  is  due  to 
tectonic  relations. 
The  fossiliferous  horizons  of  Eaibl  strata  exposed  in  Enneberg 
and  Ampezzo  represent  the  Myophoria-be&s  and  the  slightly  higher 
Ostrcea  montis-caprilis  horizon  of  the  typical  species  of  Eaibl  strata 
near  Eaibl.  The  unfossiliferous  variegated  marls,  the  thin-bedded 
dolomitic  flags,  the  beds  of  gypsum  and  dolomite,  and  the  rauch- 
wackes  which  succeed  the  fossiliferous  Eaibl  Beds  in  Enneberg  and 
Ampezzo,  represent  at  least  in  part  the  ‘  Torer  ’  or  highest  horizon 
of  the  ‘  Eaibl  ’  succession. 
On  several  of  the  dolomite-massifs  (Gardenazza,  Sella,  etc.)  the 
rock  immediately  underlying  the  Myoplioria-horizon  is  dolomitic, 
but  is  not  the  characteristic  drusy  Schlern  Dolomite.  This  variable 
thickness  of  dolomitic  shaly  flagstone  or  sandy  rock  is  of  Lower  Eaibl 
age.  At  Schlern  the  unique  development  of  fossiliferous  4  Schlern 
Plateau’  Beds  has  been  proved  by  the  recent  work  of  Wohrmann 
and  Koken  (see  footnote,  p.  42)  to  be  of  Lower  Eaibl  age.  I 
found  no  exactly  corresponding  fauna  in  the  districts  of  Enneberg 
and  Ampezzo. 
Thus,  in  the  Eaibl  period  also,  the  occurrence  of  rock-facies  is 
recognizable  in  the  district  from  Schlern  to  the  Diirrenstein,  while 
the  dolomitic  or  flaggy  development  of  Lower  Eaibl  beds  extends 
higher  in  the  Diirrenstein  district  than  in  Enneberg  or  Ealzarego. 
In  the  Eaibl  strata  on  Platz  Wiese  (Diirrenstein  district)  no 
Myophoria  or  Ostrcea  montis-caprilis  beds  are  present,  but  the 
highest  marls-and-rauchwacke  horizon  succeeds  a  continuously  dolo¬ 
mitic  development. 
Inequalities  of  thickness  are  remarked  in  the  rocks  of  all  horizons 
from  the  Muschelkalk  to  the  Dachstein  Dolomite ;  these  inequali¬ 
ties  are  correlated  with  the  frequent  occurrence  of  ashy  beds 
and  of  augitic  volcanic  rock  during  the  Buchenstein,  Wengen,  and 
St.  Cassian  periods,  and  with  the  highly  magnesian  and  ferruginous 
contents  of  the  sea-water  during  the  Schlern-Dolomite  and  Eaibl 
periods. 
The  accompanying  diagram  illustrates  the  general  stratigraphical 
relations  in  the  districts  examined. 
The  fossils  found  in  the  various  localities  are  enumerated  in 
the  appended  list.  I  must  express  my  thanks  to  Herr  von  Suttner, 
of  Munich,  for  having  kindly  identified  the  ammonites ;  and  to 
Herr  Sohle,  who  was  good  enough  to  identify  the  fossils  found  on 
Stuores  during  the  second  season  of  my  field-work. 
