202         CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,    1907,   PART   II. 
GEOLOGY. 
STRATIGRAPHY. 
GENERAL    SECTION. 
The  sedimentary  rocks  outcropping  in  these  coal  fields  comprise  an 
extensive  series  of  rocks  ranging  from  Carboniferous  limestone  to  the 
Wasatch  formation.  In  general  the  beds  outcrop  in  a  series  of  bands 
forming  a  regular  succession  from  the  "Red  Beds"  at  the  base  of  the 
mountains  eastward  to  the  badlands  of  the  Wasatch.  A  section  of 
the  strata  measured  at  Cody,  where  the  beds  are  clearly  exposed,  is 
set  forth  in  the  following  table: 
Section  of  coal-bearing  and  associated  rocks  exposed  along   Shoshone   River  near   Cody, 
Wyo. 
System. 
Formation. 
Thickness 
(feet). 
Characteristics. 
Was 
Unc< 
Fort 
Unc( 
Lara 
atch  formation. 
Various  colored  shales  mterbedded  with  sand- 
stone and  conglomerate. 
Tertiary. 
Union  formation. 
3.100 
Gray  to  drab  sandy  shale  and  tan-colored  mass- 
ive sandstone.  In  the  lower  part  of  the  for- 
mation conglomerates  occur  at  intervals 
through  1,000  feet  of  strata. 
mie  (?)  formation. 
2,630 
Dull  green  sandy  shale  with  local  brown  leaf- 
bearing  beds  and  gray  massive  sandstone. 
ft 
PI 
O 
Undifferentiated 
Montana. 
760 
In  lower  part  gray  massive  sandstone  and  dark- 
colored  sandy  shale  in  alternating  layers;  in 
upper  part  dark  and  light  gray  shales  alter- 
nating, and  numerous  lignitic  beds. 
Cretaceous. 
Eagle  sandstone. 
220 
Gray  massive  sandstone,  weathering  tun,  and 
gray  sandy  shale  with  dark  coaly  bands.  Lo- 
cally coal-bearing. 
Colorado  shale. 
3,375 
Black  to  dark  gray  shale  with  rusty  sandstone 
at  base  and  gray  massive  sandstone  at  short 
intervals  in  lower  half.  Thin  beds  of  coal 
occur  a  little  below  the  middle 
Cloverly  formation. 
300 
Gray,  green,  and  maroon  shales  and  gray  com- 
pact sandstone. 
As  shown  in  the  above  table,  the  thickness  of  sandstone  and  shale 
between  the  top  of  the  Colorado  formation  and  the  great  uncon- 
formity at  the  base  of  the  Wasatch  formerly  mapped  by  Fishera  as 
" Laramie  and  associated  formations"  is  here  tentatively  subdivided 
into  Eagle,  undifferentiated .  Montana,  Laramie (?),  and  Fort  Union. 
These  formations  are  suggested  on  lithologic  and  paleontologic  evi- 
dence, which,  however,  is  not  sufficiently  conclusive  for  final  decision. 
At  the  beginning  of  the  field  season,  in  the  absence  of  definite  fossil 
o  Fisher,  C  A.,  Prof.  Paper  U.  S.  Geol.  Survey  No.  53,  1906,  p.  8. 
