544  Intelligence  and  Miscellaneous  Articles. 
numerous  suite  of  fossils.  He  considered,  however,  that  these  beds 
did  not  belong  to  the  typical  Yorkshire  area,  but  were  the  thin  end 
of  the  series  which  stretches  across  England.  He  supposed  there  had 
been  a  carrier  in  Carboniferous  times,  which  had  separated  the  coal- 
fields of  Yorkshire  and  Durham,  prevented  the  continuity  of  the 
Permian  beds,  and  curved  round  the  secondary  rocks  to  the  north 
of  it,  to  form  the  real  Yorkshire  basin,  while  these  beds  at  Cliff  were 
immediately  to  the  south  of  it. 
The  sections  described  were  six  in  number,  the  first  pit  yielding 
the  great  majority  of  the  fossils,  and  the  third  showing  best  the 
succession  of  the  beds.  The  fossils  could  be  mostly  identified  with 
known  forms,  and  showed  a  striking  similarity  to  the  Hettangian 
fauna.  In  all  the  clays  of  the  Infra-lias,  Poraminifera  were  numerous 
and  varied. 
The  section  in  pit  No.  3  showed,  commencing  at  the  top  : — 1.  Stone 
bed  with  Am.  angulatus  (the  f ossiferous  bed  of  pit  No.  1).  2.  Thick 
clays,  with  bands  of  stone  characterized  by  Am.  Johnstoni.  3.  One 
band  of  clay  with  Am.  planorhis.  4.  Thin-bedded  stones  and  clays, 
some  of  them  oyster-bands.  5.  Clays  without  Poraminifera,  and 
with  impressions  of  Anatina  (White  Lias). 
The  Avicula-contorta  series  is  not  reached;  nor  are  there  any. 
signs  of  the  bone-bed,  as  the  junction  with  the  Keuper  marls,  which 
are  found  three  miles  off,  is  not  seen. 
The  paper  was  followed  by  references  to  the  fossils  mentioned, 
including  the  description  of  those  that  are  considered  new. 
LXVIII.  Intelligence  and  Miscellaneous  Articles. 
RESEARCHES  ON  THE  REFLECTION  OF  HEAT  AT  THE  SURFACE  OF 
POLISHED  BODIES.       BY  M.  P.  DESAINS. 
TXJHEN,  with  rock-salt  apparatus,  we  form  the  spectrum  of  lime  or 
*  *  of  incandescent  platinum,  we  find  at  the  least  refracted  ex- 
tremity of  those  spectra  lines  completely  absorbable  by  thin  layers  of 
water  or  even  of  glass.  These  lines  are  reflected  at  the  surface  of 
polished  metals  in  much  greater  proportion  than  the  red  lines  in  their 
vicinity ;  and  in  all  these  characters  they  very  nearly  resemble  those 
emitted  by  lamp-black  heated  to  only  200°  or  300°  C.  It  has  more- 
over been  long  admitted  that  the  heat  from  obscure  sources  is  re- 
markably less  refrangible  than  luminous  heat  in  its  passage  through 
a  prism  of  rock-salt. 
Some  years  since  I  studied  the  reflecting  action  of  glass  and  rock- 
salt  on  rays  from  a  source  at  a  low  temperature  ;  and  I  ascertained 
that  when  the  incident  flow  was  completely  polarized  in  the  plane 
of  incidence,  Fresnel's  formula  I2=  g.  2 ,.      ,    represents    exactly 
the  course  of  the  phenomenon  :  i  is  the  angle  of  incidence,  always 
connected  with  the  angle  r  by  the  relation  sin2=ftsinr.     In  the 
