Yol.  49.] 
ANTHRACOPIERA  AX'D  ANTHRACOMYA. 
263 
Anthracomya  Phillipsii,  R.  Etheridge,  Jim.,  Geol.  Mag.  for  1877,  pp.  243- 
244,  pi.  xii.  figs.  0,  7. 
Specific  Characters. — Transversely- obliquely  oval,  modioliform, 
elongated  in  the  direction  of  the  diagonal.  Anterior  end  obsolete, 
its  margin  rounded;  posterior  end  compressed,  expanding  into  the 
hinge-line,’  which  is  elevated  posteriorly.  Hinge-line  straight, 
almost  half  the  length  of  the  diagonal  of  the  shell.  Ventral  margin 
convex,  passing  with  a  gentle  curve  into  the  anterior  end,  or  be¬ 
coming  straight  shortly  before  it  reaches  the  anterior  end.  Beaks 
anterior,  almost  terminal,  very  obtusely  rounded  and  inconspicuous  ; 
in  the  uncrushed  condition  there  is  no  diagonal  ridge.  The  shell 
is  tumid,  becoming  flattened  above  posteriorly. 
Interior  unknown. 
Exterior. — The  markings  consist  of  concentric  lines  and  fine  stride. 
Size. — Antero-posterior  measurement,  20  mm.  (4-  inch) ;  dorso- 
ventral,  10  mm.  (|  inch);  lateral,  8  mm.  (|  inch);  another  speci¬ 
men,  23  mm.  (1-  inch),  15  mm.  (  inch),  and  5  mm.  (T  inch)  respec¬ 
tively. 
Remarks. — This  shell  has  a  very  wide  distribution,  both  hori¬ 
zontally  and  vertically.  It  must  have  existed  in  immense  numbers, 
especially  in  the  upper  beds  of  the  Coal  Measures,  and  was  gre¬ 
garious. 
Prof.  T.  Rupert  Jones,  P.R.S.,  loc.  supra  cit .,  points  out  the 
general  resemblance  of  this  shell  to  Estheria,  and  suggests  that  the 
small  shells  figured  by  Salter  in  4  Iron  Ores  of  South  Wales,’  pi.  ii. 
figs.  1-5,  are  forms  of  this  species,  the  black  bands  in  which  it  there 
occurs  being  very  characteristic  of  its  situation  ;  but  I  describe  these 
forms  under  A.  minima  below.  The  Bassy  Mine  Ironstone  and  Shale 
of  Yorth  Staffordshire  are  literally  filled  with  compressed  shells  of 
this  species,  with  Stigmaria  and  other  plant-remains. 
Phillips,  4  Silurian  System,’  p.  88,  in  a  letter  quoted  by  Murchison, 
describes  four  different  shells  (Unios)  as  occurring  in  these  beds. 
44  One,  smooth,  tumid,  with  prominent  beaks,  but  with  very  distinct 
lines  of  growth,  and  rather  short,  straight  hinge-lines,  looks  like  a 
young  Mocliola ;  a  second  form,  with  nearly  elliptical  hinge-line, 
deviating  considerably  from  parallelism  with  the  front,  ends  in  a 
prominent  angle  ;  lines  of  growth  strong,  shell  very  thin,  beaks 
slightly  prominent.  Mr.  Williamson  has  inaccurately  referred  this 
shell  to  Unio  nuciformis.  It  occurs  in  the  red  beds  above  the 
limestone,  Black  Bass,  and  underlying  Coal  Measures.” 
A  third  species,  44  which  I  named  U.  linguiformis  ( U.  Phillipsii 
of  Williamson),  is  transversely  elongated,  three  times  as  wide  as 
long ;  the  hinge-line  deviates  very  little  from  parallelism  to  the 
front  lines  of  growth  ;  shell  fine,  very  thin,  and  smooth.” 
The  fourth  species, 44  which  I  named  U.  rugulosus ,  is  of  obliquely 
expanded  or  semi-elliptical  form,  the  hinge-line  forming  the  dia¬ 
meter  [I  suppose  he  means  when  both  valves  are  lying  flattened  out, 
connected  with  a  hinge]  ;  surface  concentrically  marked  with  broken 
undulations,  often  showing  radiations  on  the  posterior  slopes  ;  shell 
exceedingly  thin.  IJnionidae  of  the  same  species  occur  in  the  bed 
