ANNIE    LAURIE    MINE,   UTAH.  89 
great  masses  of  rhyolite  tuffs  to  the  north  of  the  Annie  Laurie.  They  arc  confined  to  the 
dacite  already  mentioned  as  occurring  near  the  mines.  The  Annie  Laurie  vein  courses 
nearly  north  and  south  and  dips  from  45°  to  60°  W.  About  a  mile  to  the  west  is  a  parallel 
vein  called  the  Sevier,  on  which  the  Sevier  Mining  Ccmpany  is  now  erecting  a  mill.  The 
extension  of  the  Sevier  toward  the  north  is  being  sought  for  in  the  Holland  tunnel. 
The  Annie  Laurie  vein  is  very  poorly  exposed  on  the  surface,  being  largely  covered  by 
morainal  material.  There  is,  however,  a  large  outcrop  rising  boldly  above  the  Blue  Bird 
tunnel,  and  this  formed  the  point  of  discovery.  The  vein  has  not  been  found  on  the 
surface  at  any  point  north  of  this.  Within  a  moderate  distance  north  from  the  northern-, 
most  workings  the  Annie  Laurie  vein  should  enter  the  rhyolite.  How  this  will  affect  the 
deposit  is  as  yet  problematical.  On  the  surface  none  of  the  productive  veins  appear  to 
occur  in  this  rock. 
The  quartz  forms  an  almost  continuous  sheet  along  the  vein,  rarely  less  than  3  feet  in 
thickness  and  often  expanding  to  a  width  of  20  feet  or  more.  As  a  rule  the  walls  are  poorly 
defined  and  slickensides  indicating  motion  are  rare.  In  places  it  contains,  parallel  to  the 
walls,  streaks  of  iron  oxides  and  black,  sooty,  manganese  ores.  Near  the  walls  the  vein 
very  commonly  shows  brecciation,  and  the  quartz  here  often  contains  abundant  and  sharply- 
defined  inclusions  of  country  rock.  While  it  is  almost  impossible  to  obtain  fresh  rock  at 
any  place  in  the  mine,  and  chloritization  as  well  as  carbonatization  have  frequently 
occurred,  the  rock  is  not  changed  very  much  in  appearance,  and  the  included  greenish 
fragments  are  sharply  outlined  against  the  white  quartz. 
The  mine  workings  have  not  penetrated  below  the  zone  of  oxidation,  and  neither  the 
quartz  nor  the  country  rock  seem  to  contain  any  unoxidized  sulphides.  In  only  one  place, 
in  the  crosscut  of  the  lowest  tunnel,  was  some  fresher  dacite  found  which  contained  specks 
of  pyrite. 
In  addition  to  the  regular  vein,  which  is  often  referred  to  as  the  East  vein,  there  is  also 
in  certain  parts  of  the  workings  a  smaller  fissure  which  lies  a  short  distance  to  the  west  and 
which  differs  in  some  respects  from  the  former.  Its  quartz  contains  more  gold,  its  vein  is 
narrower,  and  slickensides  appear  sometimes  on  the  walls.  It  is  principally  known  from 
No.  3  tunnel,  in  the  richest  part  of  the  vein. 
Two  faults  with  a  throw  of  20  and  40  feet  are  known  on  the  Blue  Bird  and  No.  4  levels, 
but  on  the  whole  the  vein  is  little  disturbed. 
The  ore  consists  of  a  white,  normal  vein  quartz,  often  very  friable,  breaking  easily  into 
small  fragments.  It  is  sometimes  drusy,  but  more  commonly  massive.  Calcite  is  abundant 
in  certain  parts  of  the  deposit,  but  has  often  been  dissolved  by  surface  waters,  leaving  a 
hackly  or  lamellar  quartz  of  striking  appearance.  As  a  rule  no  ore  minerals  are  visible, 
although  on  panning  the  quartz  may  yield  a  little  visible  gold.  The  pyrite  which  the  ore 
contained  is  doubtless  converted  to  limonite,  while  the  decomposition  of  the  carbonates 
has  resulted  in  the  formation  of  oxides  of  manganese  as  well  as  more  limonite.  A  slight 
copper  stain  appears  in  places,  especially  where  the  ore  is  rich.  Finely  divided  argentite 
is  no  doubt  present,  but  only  in  small  quantities.  On  concentration  the  ore  yields  a  very 
small  quantit}^  of  sulphides,  which  are  extremely  rich  in  silver. 
The  value  of  the  gold  in  the  ore  exceeds  that  of  the  silver.  Samples  of  ore  of  the  East 
vein  yield,  for  instance,  gold,  $12;  silver,  $2.30;  or  gold,  $5.60;  silver,  $2.05.  Samples 
from  the  West  vein  contain,  for  instance,  gold,  $11 ;  silver,  32  cents;  or  gold,  $4.80;  silver, 
68  cents.  The  richest  ore  is  stated  to  assay  from  $15  to  $18  per  ton,  odd  samples  fre- 
quently rising  to  $100  per  ton.  The  average  value  of  the  ore  is  said  to  be  between  $7  and  $8 
per  ton.  The  bullion  obtained  from  the  zinc  boxes  is  stated  to  be  0.925  fine.  One  analysis 
shows  230  parts  of  gold,  695  parts  of  silver,  65  parts  of  zinc,  and  10  parts  of  copper,  the  zinc 
being  derived  from  the  shavings  in  the  boxes.  The  average  bullion  would  contain  about 
750  parts  silver  and  250  parts  gold. 
The  ore  of  the  Sevier  mine  is  in  general  similar  to  that  of  the  Annie  Laurie,  although  a 
drusy  structure  is  more  common ;  in  places  well-crystallized  masses  of  amethyst-colored 
quartz  appear.     It  is  said  that  22  per  cent  of  the  gold  values  and  7  per  cent  of  the  silver 
