PORTLAND    CEMENT    MATERIALS    IN    EASTERN    WYOMING.       237 
Of  three  samples  analyzed,  one  (analysis  1  below)  was  collected 
immediately  south  of  the  point  where  the  road  from  Newcastle  to  the 
L  A  K  ranch  crosses  Salt  Creek.  The  shale  here  is  dark  gray  and  fissile. 
No  gypsum  was  seen  at  this  point,  although  some  fragments  of  shale 
are  covered  with  a  yellowish  coating  which  has  an  astringent  taste, 
probably  due  to  the  presence  of  ferrous  sulphate.  The  second  sample 
(analysis  2)  was  collected  at  a  point  2\  miles  southeast  of  Newcastle, 
between  the  wagon  road  and  the  railroad.  Here  the  shale  is  black 
and  fissile  and  dips  gently  to  the  southwest.  The  hill  from  which  the 
sample  was  taken  is  40  feet  high,  and  the  surrounding  valley  is  under- 
lain by  shale,  presumably  of  similar  composition.  The  shale  contains 
numerous  crystals  of  gypsum,  and  gypsum  occurs  also  in  thin  plates 
along  the  joint  faces.  It  is  soft  and  could  doubtless  be  worked  by  a 
steam  shovel  with  but  little  blasting.  The  third  sample  was  collected 
from  a  hill  1^  miles  south  of  east  of  Newcastle,  near  a  prominent 
ridge  formed  by  the  sandstone  lens  in  the  Graneros  shale.  At  this 
place  there  is  a  large  body  of  gray  shale  without  sand  grains  or 
gypsum,  but  its  analysis  is  much  less  satisfactory  tLan  those  of  the 
two  previous  samples.  Analysis  1,  below,  is  by  A.  J.  Phillips  and 
P.  II.  Bates;  analyses  2  and  3  are  by  P.  II.  Bates. 
Analyses  of  samples  of  Graneros  shale. 
Constituent. 
Silica  (Si(),) 
Alumina  ( A1203) 
Ferric  oxide  (Fe203) 
Manganese  oxide  (MnO). . . 
Lime(CaO) 
magnesia  (MgO) 
Sulphuric  anhydride  (S03). 
Alkalies^0 " 
Water  at  100°  C 
Ignition  loss 
1. 
2. 
67.  55 
58.82 
17.58 
16.43 
.47 
4.47 
.18 
.24 
.36 
.54 
.74 
1.68 
.50 
1.32 
.21 
.33 
.79 
2.18 
6.39 
7.93 
11.68 
100. 26 
100.33  , 
68.  30 
14.65 
.37 
.33 
1.  18 
1.03 
.09 
.30 
.39 
6.82 
6.56 
100.02 
Analyses  1  and  2  show  a  normal  shale  with  a  high  content  of  silica 
and  a  ratio  of  silica  to  iron  and  alumina  that  would  make  the  rock  a 
satisfactory  cement-making  material.  Analysis  1,  however,  shows  a 
percentage  of  ferric  oxide  so  small  that  the  cement  mixture  would  be 
infusible,  but  analysis  2  is  in  every  way  that  of  a  shale  well  fitted  for 
making  Portland  cement.  Analysis  3  shows  that  the  rock  analyzed 
contains  entirely  too  much  silica  and  too  little  ferric  iron  to  be  of  value. 
Pierre  shale. — Pierre  shale  covers  a  large  area  lying  south  and  south- 
west of  Newcastle,  the  nearest  exposures  being  situated  3  miles  from 
town.  The  Pierre  is  a  dark-gray  shale,  about  1,250  feet  thick.  It  is 
Bull.  315—07 16 
