﻿0E 
  DIAMONDS 
  IX 
  SOUTH 
  AFRICA. 
  59 
  

  

  were 
  found 
  in 
  this 
  drift. 
  Some 
  localities 
  have 
  yielded 
  immense 
  

   quantities, 
  as 
  Pniel, 
  Klipdrift, 
  &c. 
  

  

  The 
  newer 
  one, 
  or 
  " 
  recent 
  " 
  drift, 
  occupies 
  the 
  present 
  river- 
  

   bed. 
  It 
  differs 
  in 
  composition 
  from 
  the 
  older 
  drift, 
  in 
  containing 
  a 
  

   larger 
  percentage 
  of 
  sandstone 
  pebbles 
  and 
  pebbles 
  of 
  soft 
  rocks. 
  

   Its 
  general 
  colour 
  is 
  greyish, 
  while 
  the 
  older 
  drift 
  is 
  of 
  a 
  reddish 
  

   colour. 
  The 
  newer 
  drift 
  contains 
  the 
  same 
  well-rounded 
  polished 
  

   pebbles 
  of 
  agate 
  &c. 
  as 
  the 
  older 
  one. 
  

  

  Diamond-workings 
  have 
  been 
  successfully 
  prosecuted 
  for 
  a 
  conside- 
  

   rable 
  distance 
  along 
  the 
  Vaal 
  river. 
  In 
  the 
  newer 
  drift 
  " 
  Cawood's 
  

   Hope" 
  was 
  an 
  unusually 
  rich 
  digging; 
  while 
  "Waldeck's 
  Plant 
  yielded 
  

   the 
  largest 
  diamond 
  yet 
  found 
  in 
  S. 
  Africa 
  ; 
  its 
  weight 
  is 
  288 
  carats. 
  

  

  The 
  gems 
  found 
  in 
  the 
  drift-workings 
  are 
  of 
  finer 
  quality, 
  and 
  

   invariably 
  command 
  a 
  higher 
  price 
  than 
  those 
  obtained 
  from 
  the 
  

   various 
  " 
  dry 
  diggings." 
  

  

  A 
  very 
  extensive 
  development 
  of 
  " 
  glacial 
  conglomerate 
  " 
  spreads 
  

   over 
  the 
  country 
  along 
  the 
  course 
  of 
  the 
  Orange 
  River, 
  west 
  of 
  

   Hope 
  Town 
  (lat. 
  29° 
  S.). 
  Further 
  west 
  it 
  leaves 
  the 
  river 
  to 
  the 
  

   north, 
  and 
  spreads 
  as 
  a 
  belt 
  through 
  Bushmanland. 
  Isolated 
  tracts 
  

   occur 
  near 
  Beaufort 
  West. 
  

  

  At 
  Prieska, 
  on 
  the 
  Orange 
  river, 
  diamonds 
  were 
  found 
  in 
  this 
  

   conglomerate. 
  Several 
  have 
  been 
  found 
  on 
  its 
  surface 
  between 
  

   Prieska 
  and 
  Hope 
  Town, 
  notably 
  the 
  " 
  Star 
  of 
  S. 
  Africa." 
  

  

  Systematic 
  search 
  is 
  not 
  likely 
  to 
  meet 
  with 
  much 
  reward 
  in 
  the 
  

   case 
  of 
  this 
  conglomerate, 
  as 
  the 
  very 
  nature 
  of 
  its 
  formation 
  forbids 
  

   the 
  hope 
  of 
  diamonds 
  being 
  thickly 
  distributed 
  in 
  it. 
  

  

  Many 
  of 
  the 
  hard 
  boulders 
  are 
  scored 
  and 
  scratched 
  in 
  such 
  a 
  

   manner 
  as 
  to 
  leave 
  no 
  doubt 
  concerning 
  its 
  origin. 
  

  

  That 
  the 
  wind 
  has 
  acted 
  as 
  an 
  agent 
  in 
  the 
  distribution 
  of 
  dia- 
  

   monds, 
  though 
  perhaps 
  of 
  small 
  ones 
  only, 
  is 
  clearly 
  proved 
  by 
  their 
  

   occurrence 
  in 
  the 
  drifting 
  sandy 
  soil 
  at 
  Du 
  Toit's 
  Pan. 
  It 
  has, 
  no 
  

   doubt, 
  been 
  the 
  means 
  by 
  which 
  the 
  streaks 
  of 
  sand 
  found 
  to 
  a 
  con- 
  

   siderable 
  depth 
  in 
  the 
  pipes 
  were 
  supplied. 
  

  

  A 
  complete 
  series 
  of 
  the 
  diamond-field 
  rocks 
  has 
  been 
  placed 
  in 
  the 
  

   British 
  Museum. 
  Their 
  arrangement 
  in 
  the 
  country 
  is 
  shown 
  by 
  the 
  

   accompanying 
  section 
  from 
  Port 
  Nolloth 
  to 
  Colesberg 
  Kopje 
  (fig. 
  2). 
  

  

  Discussion. 
  

  

  Mr. 
  Maskelyne 
  complimented 
  the 
  author 
  on 
  the 
  contribution 
  

   which 
  he 
  had 
  made 
  to 
  geological 
  science, 
  by 
  showing 
  that 
  the 
  rock 
  

   in 
  which 
  the 
  diamonds 
  occur 
  is 
  confined 
  to 
  the 
  pipes 
  such 
  as 
  he 
  had 
  

   described. 
  He 
  was 
  able, 
  from 
  specimens 
  which 
  he 
  had 
  examined, 
  

   to 
  state 
  positively 
  that 
  this 
  certainly 
  igneous 
  rock 
  differed 
  essen- 
  

   tially 
  from 
  the 
  dolerites 
  and 
  other 
  igneous 
  rocks 
  in 
  the 
  neighbour- 
  

   hood. 
  He 
  would 
  not 
  attempt 
  to 
  give 
  it 
  a 
  name, 
  whether 
  gabbro, 
  

   euphotide, 
  or 
  any 
  other 
  designation. 
  The 
  materials, 
  so 
  far 
  as 
  they 
  

   could 
  be 
  determined 
  in 
  their 
  present 
  altered 
  condition, 
  were 
  such 
  as 
  

   would 
  not 
  build 
  up 
  any 
  one 
  of 
  the 
  known 
  rocks. 
  There 
  were 
  

   garnets, 
  and 
  minerals 
  resembling 
  clinochlore, 
  smaragdite, 
  phlogopite, 
  

   diallage, 
  and 
  calcite, 
  and 
  apparently 
  another 
  mineral 
  entirely 
  ser- 
  

  

  