﻿540 
  Geological 
  Society 
  : 
  — 
  

  

  January 
  19th. 
  — 
  Dr. 
  Henry 
  Hicks, 
  F.R.S., 
  President, 
  

   in 
  the 
  Chair. 
  

  

  The 
  following 
  communications 
  were 
  read 
  : 
  — 
  

  

  1. 
  ' 
  On 
  some 
  Gravels 
  of 
  the 
  Bagshot 
  District.' 
  By 
  Horace 
  W. 
  

   Monckton, 
  Esq., 
  F.L.S., 
  E.G.S. 
  

  

  The 
  author 
  refers 
  to 
  his 
  papers 
  on 
  Gravels 
  South 
  of 
  the 
  Thames 
  

   published 
  in 
  the 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  for 
  1892 
  (p. 
  29) 
  and 
  1893 
  

   (p. 
  308), 
  and 
  gives 
  some 
  additional 
  details. 
  

  

  He 
  suggests 
  that 
  the 
  occurrence 
  of 
  stones 
  which 
  have 
  been 
  very 
  

   little 
  rolled 
  or 
  waterworn 
  in 
  gravels 
  at 
  certain 
  localities 
  affords 
  

   evidence 
  of 
  the 
  presence 
  of 
  ice 
  in 
  the 
  water 
  by 
  which 
  those 
  gravels 
  

   were 
  deposited, 
  and 
  that 
  the 
  position 
  of 
  some 
  sarsens 
  which 
  he 
  

   describes 
  is 
  due 
  to 
  the 
  same 
  agency. 
  

  

  He 
  gives 
  details 
  and 
  exhibits 
  photographs 
  of 
  a 
  number 
  of 
  sarsens 
  

   which 
  he 
  has 
  seen 
  in 
  sit 
  a. 
  

  

  2. 
  ' 
  On 
  the 
  Occurrence 
  of 
  Chloritoid 
  in 
  Kincardineshire.'" 
  By 
  

   George 
  Barrow, 
  Esq., 
  E.G.S. 
  

  

  The 
  rock 
  containing 
  the 
  chloritoid 
  was 
  first 
  found 
  in 
  situ 
  at 
  the 
  

   entrance 
  to 
  the 
  little 
  gully 
  at 
  the 
  head 
  of 
  Eriar 
  Glen 
  Burn, 
  near 
  

   Drumtochty 
  Castle. 
  It 
  has 
  since 
  been 
  observed 
  at 
  many 
  places 
  

   along 
  a 
  belt 
  of 
  country 
  extending 
  from 
  the 
  coast 
  north 
  of 
  Stone- 
  

   haven 
  nearly 
  as 
  far 
  as 
  the 
  North 
  Esk. 
  

  

  The 
  rock 
  is 
  easily 
  recognized 
  by 
  the 
  presence 
  of 
  numerous 
  white 
  

   spots, 
  which 
  are 
  always 
  present 
  and 
  are 
  larger 
  than 
  the 
  chloritoid. 
  

   The 
  chloritoid 
  and 
  the 
  spots 
  vary 
  in 
  size, 
  being 
  largest 
  when 
  

   the 
  rock 
  is 
  most 
  crystalline 
  (a 
  schist), 
  and 
  smallest 
  when 
  it 
  is 
  least 
  

   crystalline 
  (a 
  slate). 
  The 
  mineral 
  appears 
  as 
  minute 
  glistening 
  

   scales 
  in 
  the 
  schist, 
  but 
  in 
  the 
  slate 
  it 
  can 
  be 
  recognized 
  only 
  with 
  

   the 
  aid 
  of 
  the 
  microscope. 
  

  

  The 
  optical 
  characters 
  are 
  described, 
  and 
  shown 
  to 
  be 
  identical 
  

   with 
  those 
  of 
  the 
  mineral 
  from 
  the 
  He 
  de 
  Groix, 
  and 
  with 
  those 
  of 
  

   the 
  ottrelite 
  from 
  Ottre 
  and 
  Serpont. 
  

  

  An 
  account 
  of 
  the 
  methods 
  adopted 
  to 
  obtain 
  a 
  pure 
  sample 
  is 
  

   given. 
  Several 
  analyses 
  were 
  made, 
  and 
  it 
  was 
  proved 
  that 
  as 
  the 
  

   purification 
  increased 
  the 
  analyses 
  approximated 
  more 
  and 
  more 
  

   closely 
  to 
  the 
  analysis 
  of 
  the 
  mineral 
  from 
  the 
  He 
  de 
  Groix. 
  

  

  The 
  final 
  result 
  was 
  as 
  follows 
  : 
  — 
  

  

  Si0 
  2 
  26-00 
  

  

  A1 
  2 
  3 
  40-05 
  

  

  EeO 
  19-50 
  

  

  Ee 
  2 
  3 
  5-05 
  

  

  MgO 
  2-88 
  

  

  Loss 
  on 
  ignition 
  6-00 
  

  

  Total 
  99-48 
  

  

  The 
  author 
  discusses 
  some 
  of 
  the 
  published 
  analyses, 
  and 
  suggests 
  

   that 
  many 
  of 
  the 
  discrepancies 
  may 
  be 
  due 
  to 
  impurities 
  in 
  the 
  

   material 
  analysed. 
  

  

  