GYPSUM    OF    UNCOMPAHGR*E    REGION,    COLORADO.  403 
IV. 
Feet. 
Blue  gypsiferous  shale 6 
White  massive  sandstone 5 
Sandstone  and  shale 8 
Shale  with  gypsum  in  plates  and  gash  veins 4 
Solid  white  gypsum 4 
Gypsiferous  shale 7 
Solid  gypsum 1 
Gypsiferous  sandstone 2 
Shale 4 
Gypsiferous  sandstone 2 
Shale 2 
White  granular  gypsum 2 
Shale 8 
Gypsiferous  sandstone 18 
Red  shale 12 
Soft  white  gypsum 8 
Gypsiferous  sandstone  and  shale 40 
V. 
Shale  and  sandstone,  with  gypsum  in  beds 6 
Gypsiferous  sandstone 40 
Pinkish  to  red  sandstone 22 
Gypsiferous  sandstone 4 
Arenaceous  shale,  gypsum 22 
Solid  white  gypsum 8 
Arenaceous  shale,  gypsiferous 35 
Section  I  is  under  the  big  hill  at  the  west  bend  of  the  river,  2  miles  southwest  of  the  mouth  of  Smiths 
Fork. 
Section  II  is  at  the  big  hill  2  miles  south  of  Section  I. 
Section  III  is  near  the  sharp  eastward  bend  of  the  river  in  sec.  23,  T.  51  N.,  R.  9  W.,  about  3  miles 
south  of  Section  II. 
Section  IV  is  at  the  low  gap  2  miles  south  of  Section  III. 
Section  V  is  3  miles  south  of  Section  IV  and  2  miles  due  east  of  Devils  Elbow. 
In  the  foregoing  sections,  where  solid  gypsum  appears,  it  was  seen  at  the  surface,  but 
the  gypsiferous  shales  and  sandstones  disintegrate  very  easily,  and  the  surface  is  covered 
by  a  deep  mantle  of  loose  sand  and  clay  which  undoubtedly  conceals  many  beds  of  rock 
gypsum. 
The  great  variability  of  the  gypsum  measures  from  place  to  place  is  well  shown  in.  the 
sections,  the  only  persistent  member  being  the  bed  of  gypsum  from  4  to  8  feet  in  thickness 
which  appears  at  or  near  the  base  of  each  section. 
Along  that  portion  of  the  outcrop  covered  by  the  sections  given  above,  the  surface  is  so 
steep  that  mining  would  be  necessary  from  the  start.  The  most  easily  accessible  gypsum 
is  that  at  the  low  gap  where  Section  IV  was  taken.  The  top  of  the  gypsum  measures  is 
about  150  feet  below  the  gap,  which  may  be  reached  by  an  easy  grade  from  the  county 
road  to  the  west. 
Between  Red  Rock  Canyon  and  the  locality  of  Section  V  there  is  a  hill  sloping  gently 
westward,  the  surface  of  which  is  a  dip  slope  composed  in  part  of  the  gypsum  measures.  In 
this  region  in  places  the  gypsum  beds  lie  near  enough  to  the  surface  to  strip,  thus  saving  the 
expense  of  mining,  but  on  the  other  hand  they  are  a  thousand  feet  higher  than  the  deposit 
at  the  gap  and  the  construction  of  many  miles  of  road  would  be  necessary  to  reach  them. 
