﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  6 
  1 
  

  

  times 
  has 
  thrown 
  more 
  light 
  upon 
  the 
  life-history 
  and 
  geographical 
  

   distribution 
  and 
  extension 
  of 
  the 
  Jurassic 
  rocks 
  than 
  the 
  labours 
  of 
  

   Mr. 
  Judd 
  among 
  the 
  western 
  isles 
  and 
  on 
  the 
  west 
  coast 
  of 
  Scotland 
  

   in 
  1872 
  and 
  1877. 
  

  

  § 
  2. 
  The 
  present 
  Aspect 
  op 
  Jurassic 
  Geology. 
  

  

  In 
  1870, 
  Part 
  I. 
  of 
  a 
  memoir 
  appeared 
  in 
  the 
  ' 
  Quart. 
  Journ. 
  of 
  

   the 
  Geol. 
  Soc' 
  upon 
  " 
  The 
  Oolites 
  of 
  Northamptonshire," 
  by 
  Mr. 
  

   S. 
  Sharp, 
  E.G.S. 
  Few 
  counties 
  in 
  Mid-England 
  offer 
  such 
  advan- 
  

   tages 
  for 
  the 
  study 
  of 
  the 
  Jurassic 
  rocks. 
  Hence 
  the 
  two 
  parts 
  of 
  

   Mr. 
  Sharp's 
  memoir 
  (really 
  two 
  memoirs) 
  have 
  added 
  largely 
  to 
  the 
  

   literature 
  of 
  geological 
  science, 
  standing, 
  as 
  the 
  area 
  does, 
  midway 
  

   between 
  Oxfordshire 
  and 
  Yorkshire, 
  on 
  the 
  line 
  of 
  strike 
  of 
  the 
  

   Lower 
  Jurassic 
  rocks, 
  and 
  in 
  the 
  probable 
  centre 
  of 
  many 
  physical 
  

   changes. 
  

  

  Mr. 
  Sharp 
  recognized 
  five 
  chief 
  divisions 
  in 
  the 
  Oolites 
  of 
  North- 
  

   amptonshire, 
  three 
  in 
  the 
  Lower 
  and 
  two 
  in 
  the 
  Upper, 
  the 
  whole 
  

   five 
  having 
  a 
  thickness 
  of 
  about 
  130 
  feet 
  ; 
  the 
  lower 
  members 
  em- 
  

   brace 
  the 
  " 
  Northampton 
  Sand 
  " 
  or 
  Inferior 
  Oolite, 
  and 
  together 
  

   contain 
  81 
  genera 
  and 
  238 
  species. 
  

  

  The 
  several 
  areas 
  are 
  carefully 
  described. 
  They 
  are 
  : 
  — 
  I. 
  Kings- 
  

   thorpe 
  ; 
  II. 
  Northampton 
  ; 
  III. 
  Duston 
  ; 
  and, 
  IV. 
  Blisworth. 
  De- 
  

   tailed 
  sections 
  are 
  given 
  of 
  the 
  physical 
  features 
  of 
  each 
  area. 
  

   The 
  Ironstone-beds 
  of 
  the 
  Northampton 
  Sands 
  are 
  doubtless 
  upon 
  

   the 
  same 
  horizon 
  as 
  the 
  Dogger 
  in 
  Yorkshire, 
  the 
  ferruginous 
  

   beds 
  of 
  Glaizedale, 
  and 
  the 
  Ironstones 
  of 
  the 
  " 
  ridge" 
  in 
  Lincoln- 
  

   shire. 
  Full 
  evidence 
  has 
  not 
  occurred 
  to 
  show 
  that 
  they 
  can 
  be 
  

   identified 
  with 
  the 
  Upper 
  Liassic 
  Sand 
  of 
  the 
  Gloucestershire 
  Cot- 
  

   teswolds. 
  The 
  Great-Oolite 
  fauna 
  of 
  Kingsthorpe, 
  Duston, 
  and 
  

   Blisworth 
  is 
  remarkable 
  for 
  its 
  richness 
  in 
  bivalve 
  Mollusca 
  ; 
  for 
  

   out 
  of 
  the 
  total 
  of 
  72 
  genera 
  and 
  195 
  species 
  in 
  all 
  classes, 
  40 
  genera 
  

   and 
  125 
  species 
  belong 
  to 
  that 
  group. 
  Only 
  six 
  species 
  of 
  Brachio- 
  

   poda 
  are 
  known 
  — 
  two 
  Rhynchonellaz, 
  and 
  four 
  Terebratuloe. 
  The 
  

   Ammonitidae 
  are 
  represented 
  by 
  two 
  species 
  — 
  A. 
  gracilis 
  and 
  a 
  

   small 
  form 
  ; 
  and 
  these, 
  with 
  a 
  doubtful 
  Belemnite, 
  and 
  three 
  

   Nautili, 
  or 
  six 
  species 
  in 
  all, 
  represent 
  the 
  Cephalopoda. 
  The 
  

   Echinoidea 
  possess 
  eleven 
  species. 
  The 
  six 
  genera 
  occurring 
  at 
  

   Kingsthorpe 
  and 
  Blisworth 
  are 
  Acrosalenia, 
  Hemicidaris, 
  Clypeus, 
  

   Echinobrissus 
  and 
  Holectypus. 
  Two 
  Pentacrini 
  are 
  doubtful 
  forms. 
  

   Hybodas, 
  Lepidotus, 
  Pholidophorus, 
  Pycnodus 
  (P. 
  BucMandi), 
  and 
  

   Strophodus 
  magnus 
  and 
  S. 
  subreticulatus 
  are 
  all 
  the 
  fishes 
  known. 
  

   These 
  72 
  genera 
  and 
  195 
  species 
  are 
  distributed 
  through 
  the 
  three 
  

   areas 
  in 
  the 
  following 
  proportions 
  : 
  — 
  

  

  Kingsthorpe 
  158 
  species, 
  

  

  Duston 
  93 
  „ 
  

  

  Blisworth 
  106 
  „ 
  

  

  showing 
  that 
  many 
  are 
  common 
  to 
  the 
  three 
  areas, 
  as 
  would 
  be 
  ex- 
  

   pected 
  ; 
  this 
  is 
  especially 
  the 
  case 
  with 
  the 
  Lamellibranchiata. 
  

  

  