﻿Vol. 
  53.] 
  ASSOCIATED 
  BEDS, 
  IN 
  N. 
  DEVON 
  AND 
  W. 
  SOMERSET. 
  441 
  

  

  The 
  lower 
  beds 
  are 
  distinguished, 
  as 
  a 
  whole, 
  by 
  the 
  presence 
  of 
  

   grits 
  and 
  masses 
  of 
  limestone, 
  and 
  by 
  greater 
  variety 
  of 
  colour 
  and 
  

   texture/ 
  

  

  As 
  the 
  Treborough 
  Slates 
  are 
  unlike 
  any 
  slates 
  which 
  occur 
  in 
  

   the 
  typical 
  Ilfracombe 
  Beds, 
  and 
  are 
  essentially 
  like 
  the 
  slates 
  which 
  

   crop 
  up 
  in 
  the 
  adjoining 
  areas 
  to 
  the 
  south, 
  marked 
  by 
  all 
  as 
  ' 
  Morte 
  

   Slates,' 
  it 
  is 
  quite 
  clear 
  that 
  they 
  should 
  be 
  classed 
  with 
  the 
  latter, 
  

   and 
  not 
  with 
  the 
  Ilfracombe 
  Beds. 
  Moreover, 
  the 
  Ilfracombe 
  Beds, 
  

   as 
  may 
  be 
  seen 
  in 
  the 
  section 
  (fig. 
  1, 
  p. 
  439), 
  are 
  separated 
  from 
  

   the 
  Treborough 
  Slates 
  by 
  a 
  well-marked 
  fault. 
  The 
  palaeontological 
  

   evidence 
  also 
  shows 
  that 
  these 
  slates 
  belong 
  to 
  much 
  lower 
  horizons 
  

   in 
  the 
  succession 
  than 
  the 
  Ilfracombe 
  Beds. 
  The 
  stratigraphical 
  

   evidence 
  further 
  seems 
  to 
  point 
  to 
  a 
  physical 
  change 
  of 
  some 
  

   importance 
  as 
  having 
  affected 
  the 
  area 
  after 
  the 
  deposition 
  of 
  the 
  

   Treborough 
  and 
  Oakhampton 
  Slates, 
  and 
  before 
  the 
  Ilfracombe 
  

   Beds 
  had 
  been 
  laid 
  down. 
  The 
  lowest 
  Ilfracombe 
  Beds, 
  imme- 
  

   diately 
  beyond 
  the 
  fault, 
  are 
  massive 
  sandstones, 
  sometimes 
  con- 
  

   glomeratic, 
  dipping 
  away 
  to 
  the 
  north-east 
  at 
  a 
  low 
  angle 
  (about 
  

   .20°). 
  The 
  Treborough 
  Slates 
  south 
  of 
  the 
  fault, 
  on 
  the 
  other 
  hand, 
  

   dip 
  at 
  a 
  high 
  angle 
  (60° 
  to 
  80°) 
  almost 
  due 
  south. 
  ~No 
  fossils 
  had 
  

   been 
  recorded 
  from 
  the 
  Treborough 
  slate-quarries 
  until 
  we 
  discovered 
  

   them 
  in 
  1895, 
  though 
  numerous 
  forms 
  characteristic 
  of 
  Middle 
  

   Devonian 
  rocks 
  in 
  other 
  areas 
  have 
  been 
  mentioned 
  by 
  Mr. 
  Etheridge, 
  

   Mr. 
  Spencer 
  Percival, 
  and 
  others, 
  from 
  the 
  limestone-bands 
  in 
  the 
  

   Ilfracombe 
  Beds 
  to 
  the 
  north, 
  namely, 
  at 
  Goldsoncot, 
  Rod 
  Huish, 
  and 
  

   Withy 
  combe. 
  1 
  These 
  beds, 
  as 
  shown 
  in 
  the 
  section, 
  are 
  repeated 
  

   in 
  gentle 
  folds 
  with 
  a 
  general 
  inclination 
  to 
  the 
  north-east, 
  hence 
  

   away 
  from 
  the 
  Treborough 
  Slates. 
  In 
  the 
  Treborough 
  quarries 
  the 
  

   fossils 
  described 
  by 
  Mr. 
  Whidborne 
  occur 
  in 
  beds 
  below 
  the 
  lime- 
  

   stone-bands, 
  and 
  the 
  latter 
  at 
  present 
  have 
  yielded 
  only 
  fragments 
  

   of 
  encrinites 
  and 
  some 
  imperfect 
  corals. 
  These 
  limestone-bands 
  are 
  

   much 
  cleaved, 
  and 
  differ 
  greatly 
  in 
  appearance 
  from 
  any 
  of 
  the 
  

   limestones 
  in 
  the 
  Ilfracombe 
  Beds 
  to 
  the 
  north. 
  They 
  also 
  contain 
  

   much 
  more 
  argillaceous 
  material 
  than 
  the 
  latter. 
  The 
  slates 
  in 
  the 
  

   quarry 
  are 
  hard 
  and 
  well 
  cleaved, 
  and, 
  as 
  the 
  cleavage 
  runs 
  nearly 
  

   in 
  the 
  line 
  of 
  the 
  bedding, 
  the 
  fossils 
  on 
  the 
  whole 
  are 
  not 
  much 
  

   distorted. 
  The 
  most 
  characteristic 
  fossil 
  seems 
  to 
  be 
  the 
  large 
  

   Strophomena 
  (originally 
  Leptcena 
  explanala, 
  and 
  mentioned 
  by 
  

   Sowerby 
  as 
  occurring 
  in 
  the 
  then 
  so-called 
  Silurian 
  rocks 
  of 
  the 
  

   Rhenish 
  provinces), 
  of 
  which 
  a 
  great 
  number 
  of 
  specimens 
  have 
  

   been 
  collected. 
  Up 
  to 
  the 
  present 
  the 
  following 
  is 
  the 
  list, 
  as 
  made 
  

   out 
  by 
  Mr. 
  Whidborne 
  : 
  — 
  Dalmanites 
  sp., 
  Homalonotus 
  sp., 
  Gosse- 
  

   letia 
  ? 
  Kay 
  serif 
  Erech, 
  sp. 
  ?, 
  Cypricardinia 
  ? 
  sp., 
  Grammy 
  sia? 
  sp., 
  

   Spirifera 
  sp., 
  Strophomena 
  (Stropheodonta) 
  eocplanata 
  (Sowerby), 
  

   JStrepiorhynchus 
  ? 
  persarmentosus 
  (M'Coy), 
  Chonetes 
  plebeia, 
  Schnur, 
  

   Ch. 
  sarcinulata, 
  Schlotheim, 
  Petraia 
  sp., 
  Eridophyllum 
  sp., 
  Clado- 
  

   chonus 
  sp., 
  crinoid-segments, 
  and 
  sponge-spiculcs. 
  

  

  1 
  At 
  Rod 
  Huish 
  we 
  collected 
  numerous 
  corals 
  and 
  other 
  fossils 
  in 
  a 
  fine 
  

   state 
  of 
  preservation, 
  which 
  Mr. 
  Whidborne 
  at 
  once 
  recognized 
  as 
  the 
  same 
  

   species 
  as 
  those 
  found 
  in 
  the 
  Middle 
  Devonian 
  Limestone 
  of 
  Torquay. 
  

  

  