GYPSUM    DEPOSITS    OF    LARAMIE    DISTRICT,    WYOMING.         405 
|dated  Plaster  Company  since  1890.  These  beds  dip  beneath  the  limestone  and  are  there- 
fore lower  than  the  gypsum  at  Sportsman  Lake.  The  quarry  at  present  worked  lies  just 
feast  of  the  mill  and  shows  a  face  of  15  feet  of  solid  gypsum  rock,  which  will  be  increased 
;  to  probably  20  feet  with  farther  progress  into  the  hill.  The  quarry  formerly  worked  lies 
(northwest  of  the  mill  and  shows  a  face  of  8  or  10  feet.  The  dip  of  this  bed  would  carry  it 
25  or  30  feet  above  the  quarry  now  worked,  showing  the  existence  of  two  beds  at  this  point. 
(The  upper  bed  was  struck  again  near  the  point  where  the  switch  to  the  mill  leaves  the  main 
.line,  but  north  or  south  of  these  occurrences  the  gypsum  seems  to  thin  out  and  disappear. 
An  analysis  of  the  gypsum  from  the  quarry  at  the  mill  is  as  follows: 
Analysis  of  gypsum  from  Red  Buttes,  Wyo. 
[By  D.  O'Brine,  Colorado  Agricultural  College.] 
CaO 32.  5 
AI2O3 3 
Fe203 Trace. 
SiO-2 2 
S 03 46.  3 
II2O 20.  8 
100.1 
Laramie  and  vicinity. — Gypsum  is  struck  in  the  deep  borings  in  Laramie  at  a  depth  of 
about  GOO  feet,  but  does  not  seem  to  be  present  at  the  outcrop  of  its  horizon  directly  east 
of  the  city. 
Five  miles  northeast  of  Laramie,  in  the  SW.  |  sec.  2,  T.  16  N.,  R.  73  W.,  gypsum  crops 
out  at  the  north  base  of  the  small  hill  which  enters  near  the  middle  of  the  south  side  of  the 
section.     Several  test  pits  show  a  thickness  of  9  or  10  feet  of  gypsum  of  an  excellent  quality. 
OCCURRENCES  OF  GYPSITE. 
Several  valuable  deposits  of  gypsum  earth,  or  gypsite,  resulting  from  the  disintegration 
and  transportation  of  rock  gypsum,  are  found  in  the  Laramie  quadrangle.  Some  of  these 
have  been  carefully  bored  and  tested  by  parties  interested  in  their  location,  while  others 
have  been  located  by  their  effect  on  the  vegetation  growing  over  them. 
Laramie. — One  of  the  chief  deposits  of  gypsite  is  the  one  worked  by  the  Acme  Cement 
Plaster  Company,  just  south  of  the  city  of  Laramie.  The  deposit  covers  almost  the  whole 
of  sec.  4  and  has  a  depth  of  9  feet  where  worked.  The  gypsite  is  in  a  finely  divided  state 
and  goes  directly  to  the  calcining  kettles  without  grinding  or  screening.  The  accidental 
impurities  of  deposition,  such  as  sand,  clay,  and  limestone,  comprise  about  one-fifth  of  the 
whole,  but  do  not  interfere  with  its  use  for  cement  plaster.  No  plaster  of  Paris  is  made  at 
this  mill. 
Other  smaller  deposits  in  the  vicinity  of  Laramie  are  southeast  of  the  fair  grounds, 
across  Spring  Creek,  and  a  mile  northeast  of  Laramie,  in  the  SE.  \  sec.  28,  T.  16  N.,  R.  73  W. 
Other  deposits. — Another  larger  deposit  owned  by  the  Acme  Cement  Plaster  Company 
occupies  almost  all  of  sec.  4,  T.  16  N.,  R.  73  W.,  lying  east  of  the  county  road  and  over- 
lapping the  western  part  of  sec.  3. 
A  deposit  lies  along  Soldier  Creek  for  1  mile  below  and  2  miles  above  the  site  of  old  Fort 
Saunders. 
A  small  deposit  occurs  in  the  valley  of  Harney  Creek  in  the  NE.  \  sec.  21,  T.  14  N., 
R.  73  W.,  a  mile  southeast  of  Red  Buttes. 
Another  small  deposit  at  Red  Buttes,  lying  just  west  of  the  mill  and  having  a  depth 
of  5  or  6  feet,  is  worked  by  the  Consolidated  Plaster  Company.  Selected  rock  gypsum  is 
used  in  the  manufacture  of  plaster  of  Paris.  The  rejected  rock  is  mixed  with  gypsite  to 
make  cement  plaster. 
An  extensive  bed  of  gypsite  occupies  the  lower  2  miles  of  the  valley  of  Willow  Creek  to 
its  junction  with  Lone  Tree  Creek  and  extends  2  miles  below  the  junction. 
Another  gypsite  deposit  occupies  portions  of  sees.  33  and  34,  T.  14  N.,  R.  74  W. 
