ROCK  GYPSUM  AT  NEPHI,  UTAH." 
By  J.  M.  Boutwell. 
INTRODUCTION. 
The  more  important  known  gypsum  deposits  in  Utah  occur  in  the 
central  and  southern  portion  of  the  State,  in  Juab  County,  east  of 
Nephi;  in  San  Pete  and  Sevier  counties,  near  Salina;  in  Millard 
County,  at  White  Mountain,  near  Fillmore;  and  in  Wayne  County,  in 
South  Wash.  They  are  all  of  the  rock  gypsum  type  except  the 
one  near  Fillmore,  which  is  in  the  secondary  form  of  unconsolidated 
crystalline  and  granular  gypsum  blown  up  from  desiccated  playas  into 
dunes.  Deposits  are  also  known  in  Emery  County,  about  40  miles 
southeast  of  Richfield;  in  Kane  County,  near  Kanab;  in  Grand  County, 
between  the  Grand  River  and  the  La  Sal  Mountains;  in  San  Pete 
County,  near  Gunnison;  and  in  the  eastern  part  of  Washington  County, 
between  Duck  Lake  and  Rockville,  and  recently  large  deposits  of 
gypsum  have  been  reported  from  Iron  County,  at  points  so  far  from 
lines  of  transportation,  however,  as  to  make  their  exploitation  com- 
mercially impracticable  at  present. 
In  this  paper  the  character,  occurrence,  and  development  of  rock 
gypsum  near  Nephi,  Utah,  will  be  considered.  In  December,  1902, 
the  writer  visited  these  deposits  and  procured  the  data  which  form  the 
basis  for  the  following  sketch.  A  heavy  snowfall  seriously  interfered 
with  thorough  geologic  field  study,  and  entirely  prevented  careful 
investigation  of  certain  important  points.  Brief  descriptions  of  the 
general  character,  geologic  relations,  and  economic  development  of  the 
gypsum  deposits  near  Salina,  White  Mountain,  and  South  Wash  are 
given  in  the  complete  paper. 
CHARACTER   OF  DEPOSITS. 
This  immense  deposit  of  rock  gypsum  is  located  in  Juab  County,  1 
mile  east  of  Nephi,  on  the  south  side  of  the  entrance  to  Salt  Creek 
Valley.     It  is  the  largest  well-known  deposit  of  rock  gypsum  in  Utah,. 
« This  abstract  is  a  portion  of  a  paper  on  "Gypsum  deposits  in  Utah,"  which  will  appear  in  Bul- 
letin No.  223  (now  in  press),  on  "  Gypsum  deposits  in  the  United  States."  For  information  regarding 
the  history  and  development  of  this  deposit  the  writer  is  indebted  to  Mr.  F.  A.  Hyde,  manager,  sec- 
retary, and  treasurer  of  the  Nephi  Plaster  Company,  and  to  Mr.  James  Jackson,  superintendent  in 
charge  of  both  quarry  and  mill,  who  also  courteously  afforded  every  facility  for  studying  the  occur- 
rence and  exploitation  of  this  deposit. 
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