ST.  CASSIAN  STEATA  IN  SOUTHEEN  TYEOL. 
39 
Vol.  49.] 
sub-groups  recognized  throughout  the  sections  that  I  have  just 
described. 
YI.  The  Steatigeaphy  of  the  Beds  above  the 
St.  Cassian  Seeies. 
6.  The  Schlern  Dolomite.1 — The  Schlem  Dolom^gggrftirusy,  crys¬ 
talline,  greyish-white  rock,  less  splintery  than  the  Spfeola  Dolomite, 
and  breaking  up  into  debris  of  fairly  large  stones  and  blocks. 
Within  the  districts  of  Ampezzo  and  Enneberg  which  Im  have 
examined,  the  conformable  succession  of  the  Schlern  Dolomite  upon 
the  St.  Cassian  Beds  has  been  observed  at  Zwischenkofl  and  Garde- 
nazza,  Sella,  Sett  Sass,  Lagazuoi,  Tra  i  Sassi,  Diirrenstein,  and  the 
massif  east  of  Misurina.  The  thickness  is  normally  from  1000  to 
1400  feet :  but  it  varies,  e.  g.  at  the  Diirrenstein  it  is  2000  feet. 
In  all  these  mountains,  the  Schlern  Dolomite  rests  upon  the 
St.  Cassian  Beds  and  is  succeeded  by  Baibl  strata.  In  districts  south 
of  those  which  I  have  personally  examined,  such  as  Schlern  (south 
side),  Bosengarten,  etc.,  the  Schlern  Dolomite  rests  upon  the  Mendola 
Dolomite  and  has  there  a  thickness  of  3000  feet. 
Other  localities  occur  where  the  Schlern  Dolomite  is  apparently 
wanting,  or  where  it  has  a  very  slight  thickness.  One  or  two 
cases  of  the  disappearance  of  the  Schlern  Dolomite  come  within 
the  scope  of  this  paper,  and  I  shall  refer  to  them  in  considering 
the  tectonic  details  (Part  VIII.). 
Dossils  are  very  rarely  found  in  the  Schlern  Dolomite;  but  the 
occurrence  of  Gyroporella  annulata ,  Schafh.,  is  important,  as  it  is  a 
species  frequently  obtained  in  the  Wetterstein  Balk  of  Northern 
Tyrol.  Corals  occur  occasionally,  but  are  not  well  preserved. 
Among  other  casts  of  gasteropods,  a  large  species  of  Chemnitzia  has 
been  found. 
7.  The  Daibl  Strata. — The  Baibl  strata  form  a  characteristic 
series,  largely  dolomitic,  above  the  Schlern  Dolomite,  and  below 
the  Dachstein  Dolomite.  As  their  development  is  especially  subject 
to  local  variation,  a  rapid  review  of  a  few  sections  noted  within 
the  districts  examined  is  desirable.  On  the  western  slope  of  Sett  Sass 
the  Baibl  strata  are  exposed  below  the  Dachstein  Dolomite  in  the 
following  succession  (in  descending  order) : — - 
I.  Sett  Sass  (western  slope). 
Dachstein  Dolomite. 
"  Pale  greenish  or  white  dolomitic  flags. 
Variegated  dolomitic  marls,  red,  bluish  purple,  and  greenish. 
Fossils  rare  ;  only  one  found  : — Myophorici,  sp. 
-r>  -ii  Fine  conglomerate  ;  fragments  of  brightly-coloured  marls  and  of 
p,ai|  dolomite  cemented  by  a  whitish  dolomitic  sand.  This  rock  is 
very  striking,  and  occurs  frequently  at  the  same  horizon. 
Variegated  dolomitic  marls  as  above,  containing  iron  ore.  Inter- 
stratified  beds  of  dolomitic  flags  and  dolomitic  limestone. 
Brown  sandstones  containing  Myophorici  Kefersteini,  Klipst. 
1  See  Introduction  (p.  3),  where  the  different  names  hitherto  applied  by 
geologists  to  this  dolomitic  rock  are  enumerated  and  explained. 
