10 
MISS  OGILVIE  OX  THE  WEXGrEX  AXD 
[Feb.  1893, 
geological  map  and  several  sections  give  additional  value  to  bis 
original  work.  A  clear  idea  will  be  gained  of  the  succession  of 
Triassic  strata  adopted  by  that  author  from  the  important  section 
over  the  Seisser  Alpe  and  the  Schlern  mountain.1 
After  his  examination  of  the  Triassic  strata  over  a  large  tract  in 
the  west  and  south-west  of  this  district,  Richthofen  sought  to 
explain  the  peculiar  local  features  by  the  application  of  Darwin's 
theory  of  the  origin  of,  and  conditions  attending,  coral-reefs. 
Whereas  in  the  older  literature  it  had  been  suggested  that  the 
St.  Cassian  fossils,  occurring  in  marly  strata  and  limestone-beds, 
had  the  special  character  of  coral-banks  and  represented  the 
fauna  of  a  shallow  sea,  Richthofen  suggested  that  the  dolomite 
mountains  themselves  were  in  truth  altered  coral-reefs,  formed 
during  subsidence  of  the  land,  while  the  fauna  of  the  St.  Cassian 
and  of  the  Raibl  strata  had  been  developed  in  the  restricted  lagoons, 
bays,  and  channels  of  a  coral  sea. 
This  explanation2  of  the  origin  of  the  dolomite  massifs  in  Southern 
Tyrol  as  a  varying  and  disconnected  reef-facies  during  continued 
deposition  of  sedimentary  beds  has  been  accepted  and  supported, 
after  careful  original  investigations  in  the  district,  by  the  well- 
known  geologists  Stur 3  and  Mojsisovics. 
The  publication  of  the  latter’s  book,  ‘  Die  Dolomit-Riffe  von  Siid- 
Tyrol  u.  Venetien  ’  in  1879  embraces  the  work  of  several  geologists 
associated  with  him  in  a  survey  of  the  district.  A  large  extent  of 
country  was  mapped  (scale  1 :  75000),  and  Mojsisovics  entered  fully 
into  the  question  of  facies.  I11  this  work  the  nomenclature  of 
tho  strata  differs  somewhat  from  that  of  Richthofen,  e.  g.  the 
£  Sedimentary  Tuffs  ’  and  ‘  Cipit  Limestones  9  of  Richthofen  in  the 
Seisser  Alpe  section  are  included  by  Mojsisovics  as  Wengen  strata, 
and  the  name  of  ‘  St.  Cassian  strata  ’  is  limited  to  the  small 
upper  series  of  beds  containing  the  well-known  and  unusually  rich 
fauna  collected  chiefly  on  the  Stuores  meadow,  near  St.  Cassian,  in 
the  Enneberg  Valiev. 
In  developing  and  extending  the  application  of  the  coral-reef 
theory  of  Richthofen,  Mojsisovics  emphasized  the  ‘  heteropic  ’ 4 
1  ‘  G-eogn.  Beschr.  d.  Umg.  v.  Preclazzo,’  pp.  40-43. 
2  In  several  cases  Austrian  geologists  have  found  Richthofen’s  coral-reef 
theory  applicable  to  the  occurrence  of  thick  masses  of  limestone  elsewhere, 
and  in  other  formations  than  the  Trias.  I  may  mention  the  recent  work  of 
Dr.  Franz  Wahner  in  the  Rofan  Group,  near  the  Achen  See,  in  Northern 
Tyrol.  Dr.  Wahner  attributes  the  white  Liassic  limestones  of  Sonnwendjoch 
to  the  agencv  of  corals,  while  a  facies-development  of  foraminiferal  limestone 
occurs  quite  near,  on  Pfons  Joch.  Zeitschr.  d.  Deutsch.  Alpenver.  vol.  xxii.  1891. 
3  ‘  Eine  Excursion  in  der  E’mgegend  von  St.  Cassian,’  Jahrb.  d.  k.  k.  geol. 
Reichsanstalt,  1808,  p.  529. 
4  [On  p.  6  of  his  ‘Dolomit-Riffe,’  Mojsisovics  explains,  as  follows,  ‘  bete- 
ropisch’  (a  compound  apparently  derived  from  erepos  and  0^,  ottos):  — 
‘  Ebenso  wie  sich  zu  gleicher  Zeit  und  neben  einander  im  selben  Rauine 
verschiedenartige  Facies  bilden,  erscheinen  in  verschiedenen  Raumen  (Pro- 
vinzen)  und  zu  verschiedenen  Zeiten  gleichartige  Facies.  Die  ersten  nennen 
wiv  heteropische ,  die  letzteren  isopische  Bildungen.’  See  also  his  paper  ‘  Ueber 
heteropische  Verhaltnisse  im  Triasgebiete  der  lombardischen  Alpen,’  Jahrb.  d. 
k.  k.  geol.  Reichsanstalt,  1880,  p.  095. — El>.] 
