﻿412 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [June 
  8, 
  

  

  the 
  six 
  families 
  into 
  which 
  the 
  eminent 
  Dutch 
  zoologist, 
  Van 
  der 
  

   Hoeven*, 
  divides 
  the 
  Marsupials 
  now 
  existing, 
  the 
  entomophagous 
  

   and 
  sarcophagous 
  Dasyurina 
  are 
  represented 
  in 
  the 
  " 
  dirt-bed 
  " 
  of 
  

   Purbeck 
  by 
  the 
  Spalacotheriumf 
  and 
  Triconodon 
  %, 
  and 
  in 
  the 
  Stones- 
  

   field 
  slate 
  by 
  the 
  Amphitherium 
  and 
  Phascolotherium, 
  the 
  former 
  the 
  

   analogue 
  of 
  the 
  insectivorous 
  Myrmecobius 
  § 
  of 
  Western 
  Australia, 
  

   the 
  latter 
  that 
  of 
  the 
  Thylacinus\\ 
  of 
  Van 
  Diemen's 
  Land. 
  The 
  

   Pedimana 
  (Wagn.) 
  can 
  hardly 
  be 
  said 
  to 
  be 
  represented, 
  though 
  

   both 
  the 
  above 
  fossils 
  from 
  Stonesfield 
  present 
  some 
  of 
  their 
  charac- 
  

   teristics, 
  and 
  the 
  latter 
  to 
  such 
  a 
  degree 
  that 
  the 
  scale 
  of 
  evidence 
  

   inclines 
  but 
  a 
  little 
  in 
  favour 
  of 
  Thylacinus. 
  The 
  presence 
  of 
  the 
  

   Macropoda 
  (Van 
  der 
  H.) 
  (= 
  Poephaga, 
  Owen) 
  is 
  proved 
  by 
  the 
  

   discovery 
  of 
  the 
  Kangaroo-rat 
  allies 
  : 
  — 
  namely, 
  in 
  the 
  Purbeck 
  beds, 
  

   of 
  the 
  Plagiaidax, 
  the 
  true 
  affinities 
  of 
  which 
  have 
  been 
  so 
  amply 
  

   demonstrated 
  by 
  Dr. 
  Falconer^" 
  ; 
  in 
  the 
  Rhaetic 
  bone-bed, 
  of 
  the 
  

   Microlestes 
  of 
  Frome 
  and 
  Diegerloch, 
  closely 
  allied, 
  according 
  to 
  

   Professor 
  Owen, 
  to 
  Plagiaidax 
  (Paheont. 
  p. 
  303) 
  ; 
  and, 
  lastly, 
  in 
  the 
  

   strata 
  below 
  the 
  bone-bed, 
  by 
  the 
  discovery 
  of 
  the 
  Hypsiprymnopsis 
  

   Rhceticus 
  of 
  the 
  Watchet 
  shore. 
  Thus, 
  out 
  of 
  Van 
  der 
  Hoeven's 
  six 
  

   families, 
  two 
  are 
  amply 
  represented, 
  and 
  have 
  an 
  extended 
  range 
  — 
  

   the 
  entomophagous 
  and 
  sarcophagous 
  Dasyurina 
  from 
  the 
  Purbeck 
  

   to 
  the 
  Inferior 
  Oolite, 
  and 
  the 
  phytophagous 
  Macropoda 
  also 
  from 
  

   the 
  Purbeck 
  downwards 
  into 
  the 
  Lower 
  Rhsetic 
  Marls. 
  At 
  the 
  

   present 
  day, 
  of 
  the 
  Marsupials 
  but 
  a 
  few 
  species 
  of 
  the 
  Opossums 
  

   linger 
  in 
  the 
  northern 
  hemisphere, 
  in 
  Mexico, 
  California, 
  and 
  the 
  

   Southern 
  States 
  ; 
  and 
  but 
  one 
  genus 
  (Didelphys) 
  is 
  found 
  out 
  of 
  

   Australasia 
  and 
  the 
  islands 
  to 
  the 
  south-east 
  of 
  the 
  Straits 
  of 
  

   Macassar. 
  But, 
  on 
  reviewing 
  the 
  past, 
  we 
  see 
  their 
  range 
  rapidty 
  

   extending. 
  Cuvier's 
  memorable 
  discovery 
  in 
  the 
  Paris 
  Basin 
  

   extends 
  the 
  area 
  of 
  Didelphys, 
  or 
  the 
  most 
  cosmopolitan 
  of 
  the 
  

   existing 
  Marsupials, 
  to 
  Europe 
  in 
  the 
  Eocene 
  period. 
  And 
  still 
  

   further 
  back, 
  amid 
  the 
  relics 
  of 
  a 
  fauna 
  and 
  flora 
  similar 
  to 
  those 
  

   which 
  still 
  inhabit 
  the 
  area 
  now 
  occupied 
  by 
  the 
  Marsupials 
  — 
  amid 
  

   Zamice 
  and 
  Cycadece, 
  Cestracionts,and 
  Trigonice 
  — 
  the 
  few 
  Mammalian 
  

   scraps 
  that 
  have 
  escaped 
  the 
  waves 
  indicate 
  the 
  presence 
  in 
  England 
  

   of 
  members 
  of 
  one-third 
  at 
  least 
  of 
  the 
  existing 
  Marsupial 
  families. 
  

  

  from 
  that 
  of 
  any 
  animal 
  living 
  or 
  extinct. 
  On 
  the 
  faith 
  of 
  Pliolophus 
  vulpi- 
  

   cejps 
  of 
  the 
  London 
  Clay 
  being 
  less 
  unlike 
  it 
  than 
  any 
  other, 
  I 
  am 
  unwilling 
  to 
  

   admit 
  its 
  classification 
  among 
  the 
  Placental 
  herbivores. 
  (See 
  Quart. 
  Journ. 
  Geol. 
  

   Soc. 
  vol. 
  xiii. 
  p. 
  4 
  ; 
  Owen, 
  Paheont. 
  p. 
  308.) 
  

  

  * 
  Handbook 
  of 
  Zoology, 
  vol. 
  ii. 
  pp. 
  612-622, 
  8vo, 
  1858. 
  Transl. 
  by 
  Dr. 
  Clarke. 
  

  

  t 
  Owen, 
  Paheont. 
  p. 
  315. 
  

  

  \ 
  Ibid. 
  p. 
  313. 
  

  

  § 
  Owen, 
  Brit. 
  Foss. 
  Mam. 
  pp. 
  29-60 
  ; 
  Palaeont. 
  p. 
  303. 
  

  

  || 
  Owen, 
  Brit. 
  Foss. 
  Mam. 
  p. 
  67 
  ; 
  Palaeont. 
  p. 
  306. 
  

  

  *j[ 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xiii. 
  p. 
  261 
  ; 
  vol. 
  xviii. 
  p. 
  348. 
  

  

  