190  Geological  Society  : — 
in  silt-beds  south  of  Rattray  Head,  give  evidence  of  a  period  of 
considerable  submergence ;  but  the  recurrence  of  an  ice- sheet 
appears  to  have  destroyed  most  of  this  evidence,  as  is  seen  in  a 
section  at  Kino;  Edward. 
November  22nd.— J.  E.  Harr,  Sc.D.,  F.R.S.,  President, 
in  the  Chair. 
The  following  communications  were  read  : — 
1.  'Ona  New  Specimen  of  the  Chimaeroid  Fish,  31 yri acanthus 
paradoxus,  Ag.,  from  the  Lower  Lias  of  Lyme  Regis  (Dorset).'  By 
Arthur  Smith  "Woodward,  LL.D.,  F.R.S.,  F.L.S.,  F.G.S. 
2.  '  The  Rocks  of  the  Cataracts  of  the  River  Madeira  and  the 
adjoining  portions  of  the  Beni  and  MamoreV  By  John  William 
Evans,  D.Sc,  LL.B.,  F.G.S. 
The  crystalline  rocks  of  the  cataracts  of  the  River  Madeira  and 
the  lower  waters  of  its  tributaries  are  part  of  a  ridge  with  a  north- 
westerly and  south-easterly  strike,  similar  to  that  of  the  Andes  in 
the  same  latitudes.  This  strike  is  especially  prevalent  in  Equatorial 
regions.  With  the  exception  of  comparatively -recent  alluvial 
deposits  and  a  few  pebbles  of  chert,  pronounced  by  Dr.  G.  J.  Hinde 
to  be  of  marine  origin  but  uncertain  date,  only  crystalline  rocks  are 
met  with  in  the  falls.  They  all  appear  to  be  igneous,  and  are  mostly 
massive  in  character,  though  some  dyke-rocks  occur.  In  places 
they  are  typical  gneisses,  and  they  are  often  banded,  but  in  some 
cases  thej"  show  no  signs  of  foliation.  The  prevailing  type  is  acid, 
with  a  considerable  proportion  of  alkalies,  especially  soda;  but  some 
of  the  rocks  are  distinctly  basic  in  character.  Analyses  of  several  of 
these  rocks,  made  by  Mr.  G.  S.  Blake,  are  tabulated  ;  and  in  one  case 
the  chemical  analysis  is  compared  with  one  made  from  the  propor- 
tion of  minerals  washed  out  from  the  thin  sections.  Accounts  of  the 
megascopic  and  microscopic  characters  of  all  the  rocks  encountered 
are  given.  The  more  acid  rocks  are  usually  fine  in  grain,  and  are 
often  granulitic  in  structure.  In  most  cases  the  quartz  seems  to 
have  crystallized  out  before  the  felspar.  The  occurrence  of  andalu- 
site  of  chiastolitic  type  and  of  sillimanite  as  inclusions  in  a  felspar  is 
referred  to,  as  well  as  the  presence  in  one  rock  of  an  unusual  type 
of  allanite.  An  altered  basalt  is  described,  which  contains  minute 
concentric  structures  allied  to  those  of  a  pyromeride.  Above  and 
below  the  region  of  the  cataracts  is  a  wide  expanse  of  country 
covered  with  alluvium,  either  of  recent  or  later  Tertiary  date. 
3.  '  The  Doncaster  Earthquake  of  April  23rd,  1905.'  Bv  Charles 
Davison,  Sc.D.,  F.G.S. 
The  Doncaster  earthquake  of  1905  was  a  twin,  with  its  principal 
