Physical  Geography.  157

Sandstone,  Carboniferous,  Permian,  and  New  Red  form-
ations, it  will  be  seen  that,  by  the  writer,  they  are  all
considered  to  afford  evidence  of  continental  as  opposed
to  purely  marine  conditions  ;  for  the  Old  Bed  Sand-
stone was  deposited  in  fresh  water,  the  Coal-measures,
whether  below,  interstratified  with,  or  above  the  Car-
boniferous Limestone,  on  the  edges  of,  and  to  a  great
extent  on,  a  continent  with  large  rivers,  marshes,  and
beds  of  peat,  and  the  Permian  and  New  Red  series
both  in  salt  lakes ;  in  other  words,  a  great  continental
epoch  in  Northern  Europe  (and  in  other  regions),  lasted
from  the  close  of  the  Upper  Silurian  epoch  down  to
the  end  of  the  deposition  of  the  New  Red  Marl,  one
main  feature  of  ivhich  was  the  abundance  of  reptilian
life,  partly  Amphibian.  Those  parts  of  it  in  which
the  Permian  and  New  Red  strata  were  deposited  can
be  best  compared  physically  to  the  great  area  of  inland
drainage  of  Central  Asia,  so  dry  and  arid  where  not
artificially  irrigated  by  rivers,  and  in  which,  from  the
Caspian  Sea  for  3,000  miles  to  the  east,  and  far  south
towards  the  Himalayah,  in  a  comparatively  rainless
district,  all  the  lakes  are  salt,  excepting  those  which
have  an  outlet  into  some  lower  lake.
