Yol.  49.] 
ST.  CASS1AX  STRATA  IX  SOTTTHERX  ITROL. 
15 
This  series  has  been  subdivided  in  Southern  Tyrol  into  : — 
f  Upper  Musehelkalk  (=Bickthofeiis  ‘Mendola  Dolomite’). 
Characteristic  fossils :  — 
Trachyceras  trinodosum .  llojs. 
Ptychites  gibbus,  Beneeke,  etc. 
{  Lower  Huschelkaik  (  =  Richthofen's  £Yirgloria  Kalk  ’). 
Characteristic  fossils  :  — 
Trachyceras  binodosum,  Hauer. 
Ptychites  Studeri ,  Hauer. 
v  Terebratula  vulgaris,  Schloth. 
At  both  horizons  occurs  the  representative  fossil  alga.  Gyropordla 
pauciforata ,  Giimbel.  5Yhere  exposed  in  the  Euchenstein  and 
Enneberg  Talleys,  the  Lower  Yluschelkalk  Beds  are  dark,  bitu¬ 
minous,  evenly-bedded  limestones  and  shales  varying  from  10  to 
60  feet  in  thickness.  Year  Prags,  these  beds  are  at  least  300  feet 
thick  ;  in  the  lower  portion  they  are  greyish  or  reddish  limestones 
and  bituminous  shales,  succeeded  by  a  great  thickness  of  greyish- 
white  dolomitic  limestone  and  dolomite  containing  Gyroporella 
pauciforata  often  in  great  number. 
The  Upper  hluschelkalk  is  throughout  a  pure  dolomite,  drusy  and 
crystalline,  brittle,  and  forming  debris  of  small  angular  fragments. 
Although  well-bedded  in  thick  massive  layers,  the  planes  of  bed¬ 
ding  are  often  less  striking  to  the  eye  than  those  of  the  vertical 
joints  and  clefts,  and  are,  moreover,  in  some  measure  obscured  by 
the  general  effects  of  weathering.  Like  the  Lower  Yluschelkalk, 
this  dolomite  also  varies  much  in  thickness  ;  thus  in  Enneberg  it  is 
very  little  developed,  not  reaching  more  than  120—150  feet,  while 
in  the  Prags  district  it  reaches  a  maximum  thickness  of  1200  feet. 
3.  The  Buclienstein  Beds. — The  village  of  Buchenstein  or  Pieve 
(from  which  these  beds  derive  their  name)  lies  in  the  Buchenstein 
Talley,  south  of  Prelongei  and  Sett  Sass. 
The  strata  succeed  the  Yluschelkalk  conformably,  and  their  fauna 
shows  so  great  a  similarity  to  that  of  the  underlying  formation  that 
several  authors  1  have  included  them  as  a  higher  zone  of  Alpine 
Yluschelkalk.  Besides  such  typical  Upper  Yluschelkalk  fossils  as 
Terebratula  angusta ,  Schloth.,  T.  vulgaris ,  Schloth  ,  Pecten  discites , 
Schloth.,  sp.,  Trachyceras  binodosum ,  Hauer,  others  specially  cha¬ 
racteristic  of  this  horizon  occur,  e.  g.  Tr.  Beitzi.  Bockh,  Tr.  BdcJchi , 
Both.,  Hcdobia  TaranieTlii,  Afojs.,  etc. 
Hard  limestone-beds  with  siliceous  concretions,  and  the  ‘  Pietra 
Yerde'  rock  so  characteristic  of  Southern  Tyrol,  together  with 
interbedded  fossiliferous  shales,  predominate  in  the  exposures  found 
near  Buchenstein  and  farther  west.  On  the  other  hand,  the  ;  Pietra 
Yerde  ’  and  siliceous  limestones,  although  present  in  the  neighbour- 
1  See  esppcially  Loretz.  op.  cit.  Zeitschr.  d.  Deutsch.  geol.  Gesellsch.  vol.  xxvi. 
(1871)  p.  106.  etc. 
