The  Carboniferous  rocks  are  displayed  in  very  different  aspects
or  facies  in  the  various  parts  of  the  continent  and  even  in  contigu-
ous regions.  New  York  no  longer  gives  the  standard  scale,  for
that  state  has  very  little  that  is  newer  than  the  Devonian.  For
the  eastern  part  of  the  country  the  sequence  of  strata  in  Penn-
sylvania serves  as  the  scale  of  reference,  while  a  very  different
one  is  needed  for  the  Mississippi  valley.  In  the  Rocky  Mountain
region,  again,  the  character  of  deposition  deviated  markedly
from  what  occurred  in  the  East,  and  all  over  the  far  West  the
Carboniferous  is  almost  entirely  marine,  without  coal.  Even  in
this  region,  however,  the  distinction  between  the  Lower  and
Upper  Carboniferous  may  be  drawn.    The  following  table  gives

9R  609

Digitized  by  VjUUV  It:


6io


THE  CARBONIFEROUS  PERIOD


the  succession  in  England,  Pennsylvania,  and  the  middle  West,
Illinois,  Missouri,  Iowa,  etc.
CARBONIFEROUS  SYSTEM


England

Pennsylvania

Ardwick  Scries

Monongahela  Stage

Middle  Coel

1     Upper

Conemaugb  Stage

Gannister  Series

Carbonif.
Allegheny  Stage

Millstone  Grit

Pottsville  Stage

Yoredale  Series

Scaur  Limestone

Mauch  Chunk

Series

Lower

Stage

Limestone

Carbonif.
(Greenbrier)

Shales

.Pocono  Stage

Mississippi  Valley


Pennsyl-  ( Coal  Measures
vanian    I  Millstone  Grit


Missis-
sippian


Kaskaskia  Stage
St  Louis  Stage
Osage      (Warsaw

[  Burlington
Kinderhook  Stage


Distribution  of  the  Carboniferous  Rocks

American. — The  Carboniferous  is  divisible  into  two  sharply
marked  portions,  the  Lower,  or  Mississippian,  and  Upper,  or
Pennsylvanian,  a  distinction  which  is  applicable  in  all  the  con-
tinents in  which  the  strata  of  this  period  have  been  carefully
studied.
