Xiower  Permian. — The  inferior  sandstones  which  lie  beneath
the  marl-slate  consist  of  sandstone  and  sand,  separating  the
Magnesian  Limestone  from  the  coal,  in  Yorkshire  and  Durham.
In  some  instances,  red  marl  and  gypsum  have  been  found
associated  with  these  beds.  They  have  been  classed  with  the
Magnesian  Limestone  by  Professor  Sedgwick,  as  being  nearly


372  LOWER  PERMIAN.  [CH.  xxn.
co-extensive  with  it  in  geographical  range,  though  their  rela-
tions are  very  obscure.  But  the  principal  development  of
Lower  Permian  is,  as  we  have  seen  by  Mr.  Hull's  table,  p.  367,
in  the  north-west,  where  the  Penrith  sandstone,  as  it  has  been
called,  and  the  associated  breccias  and  purple  shales  are  esti-
mated by  Professor  Harkness  to  attain  a  thickness  of  3,000  feet.
Organic  remains  are  generally  wanting,  but  the  leaves  and  wood
of  coniferous  plants,  and  in  one  case  a  cone,  have  been  found.
Also  in  the  purple  marls  of  Corncockle  Muir  near  Dumfries  very
distinct  footprints  of  reptiles  occur,  originally  referred  to  the
Trias,  but  shown  by  Mr.  Binney  in  1856  to  be  Permian.  No  bones
of  the  animals  which  they  represent  have  yet  been  discovered.
Angular  breccias  in  Lower  Permian. —A  striking  feature  in
these  beds  is  the  occasional  occurrence,  especially  at  the  base  of
the  formation,  of  angular  and  sometimes  rounded  fragments  of
Carboniferous  and  older  rocks  of  the  adjoining  districts  being
included  in  a  paste  of  red  marl.  Some  of  the  angular  masses
are  of  huge  size.
