Yol.  49.] 
ST.  CASSIAS  STRATA  IN  SOUTHERN  TYROL. 
37 
Seisser  Aljoe. 
The  particular  interest  attached  to  the  exposure  of  Wengen  and 
St.  Cassian  Beds  on  the  Seisser  Alpe  lies  in  their  stratigraphical 
relations  with  the  Schlern  Dolomite  of  Schlern.  These  have  been 
discussed  at  length  in  the  works  of  Richthofen,  Giimbel,  Mojsisovics, 
and  others.1 
On  entering  the  Seisser  Alpe  from  the  Pufels  ravine,  the  augite- 
porphyry  and  tuffs  of  Lower  Wengen  age  are  succeeded  by  a  series 
of  ashy  rocks,  strike  2L  70°  E.,  dip  slightly  southward,  as  follows  : — 
Cipit  Limestone  series,  almost  entirely  eroded  from  the 
Alpe. 
Fossiliferous  marls,  interbedded  with  unfossiliferous 
earthy  tuffs,  and  ashy  shales  and  grits. 
Fossiliferous  limestone = first  Cipit  Limestone-bed  of 
Richthofen. 
Grey  shales  with  Halobia  Lommeli ,  fine  breccia  of  tuff 
and  limestone-fragments.  Black  earthy  tuffs  and 
shales. 
Plant-bearing  sandstones,  grey  limestone,  with  rough 
weathered  surface  on  which  badly-preserved  fossils 
are  observed. 
Tuffs  and  augite-porphyry — the  ‘  Regenerate  Tuffe’ 
series  of  Richthofen ;  Tachycardia  rugusa  occurs  in 
the  tuffs. 
The  Cipit  blocks  scattered  on  the  higher  parts  of  the  Seisser 
Alpe  are  yellowish-brown  limestone  full  of  lithodendroid  corals 
and  Encrinus  cassianus.  These  are  found  in  position  near  the 
source  of  the  Cipit  Bach,  hence  the  name  originally  given  by 
Richthofen. 
The  strata  on  the  Seisser  Alpe  form  a  syncline,  and  the  same 
beds  bend  upward  and  are  found  on  the  Giinserbuchl  and 
the  Mahlknecht  slopes  below  Rosszahne.  The  rocks  west  of 
Mahlknecht  are  interbedded  breccias  and  tuffs  dipping  slightly 
north.  Wedged  in  the  breccias  are  irregular  masses  of  the  Cipit 
Limestone,  and  upon  the  whole  system  the  Schlern  Dolomite  of 
Rosszahne  rests  with  a  slight  unconformity.2 
The  term  *  regenerirte  Tuffe  ’  was  applied  by  Richthofen  (op. 
cit.  p.  91)  to  the  development  of  tuffs  and  conglomerates  in  the 
Upper  Fromm  Bach  on  the  Seisser  Alpe,  previously  observed  by 
Emmrich,  and  containing  PacJiycardia  rugosa  in  great  abundance. 
Richthofen  took  these  beds  for  a  local  development  of  Raibl  strata 
resting  upon  the  sedimentary  tuffs  of  the  Seisser  Alpe,  but  Stur  3 
observed  the  continuation  of  the  4  regenerirte  Tuffe  ?  over  a  wider 
1  Richthofen,  ‘  Geogn.  Besclir.  d.  Umg.  v.  Predazzo,’  p.  40,  ‘  Seisser  Alpe- 
section  ’ ;  Giimbel,  ‘  Das  Mendel  u.  Schlern  Gebirge,’  Sitzungsb.  d.  k.  k.  Akad. 
d.  Wissensch.  Wien,  1873  (Pufler  Schlucht-section) ;  Mojsisovics,  ‘Dolomit- 
Riffe,’  p.  154;  Fraas,  ‘  Scenerie  der  Alpen,’  Leipzig,  1892,  pp.  137,  166,  etc. 
2  I  owe  this  obseiwation  at  Mahlknecht  and  Rosszahne  in  the  first  instance 
to  the  kindness  of  Dr.  Rothpletz ;  in  1892,  on  a  later  visit  to  Schlern,  I 
myself  saw  the  relations  of  the  Cipit  Limestone  and  the  tuffs  at  Mahlknecht. 
3  Jahrb.  d.  k.  k.  geol.  Reichsanstalt,  1868,  p.  541. 
Middle  St.  Cassian 
Beds  (in  part). 
Lower  St.  Cassian.  ■ 
Wengen  Beds.  •{ 
