338  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  2« 
Davis  mines. — The  Davis  mines  are  located  three- fourths  of  a  mile 
northeast  of  Lakeville,  Conn.  Extensive  open  pits  are  worked  here 
now.  Limestone  appears  at  the  surface  at  the  northeast  and  north- 
west corners  of  the  main  pit,  with  a  strike  N.  55°  E.,  and  dip  south- 
east at  an  angle  of  15°.  It  is  reported  that  limestone  was  struck 
below  the  ore  in  the  main  pit,  but  this  opening  is  now  filled  up.  No 
schist  or  quartzite  occurs  in  the  vicinity,  and  the  ore  body  is  evi- 
dently on  or  entirely  in  a  flat-lying  limestone.  Pockets  of  magresian 
ore  occur  and  are  said  to  be  most  common  near  the  bottom  of  the  dej 
posit.  The  following  is  stated  to  be  fairly  representative  of  the  secJ 
tion  shown  at  the  Davis  mines,  if  a  shaft  were  carried  down  to  the 
underlying  limestone. 
Section  at  the  Davis  mines,  near  Lakeville,  Conn. 
Feet. 
Limonite   and   clay 15-1^0 
Limonite  with  more  clay   (ocher) 20-40 
Lenses  and  pockets  of  manganese  ore 
Black    ocher 1-  5 
Blue    limestone 
Analyses  of  Davis  ores,  from  the  Tenth  Census  Report,  follow 
Nos.  3  and  4  being  of  manganiferous  ores: 
Analyses  of  ores  from  Davis  mines,  near  Lakeville,  Conn. 
Metallic  iron 
Metallic  manganese 
Phosphorus 
Phosphorus  in  100  parts  iron 
41.55 
073 
176 
44.59 
.059 
.132 
27.46 
26.60 
.045 
.164 
2.241 
25.81 
.06 
Orehill  mines. — There  is  a  group  of  mines  at  Orehill,  on  the  Ceil 
tral  New  England  Railroad,  about  2 J  miles  west  of  Lakeville.  A 
present  these  mines  are  being  extensively  worked,  the  product  beinj 
taken  by  the  Barnum  Richardson  Company,  of  Limerock,  Conn. 
The  old  pits  show  Hudson  schist  on  the  west  side,  striking  N.  4($ 
E.  and  dipping  southeastward  at  an  angle  of  45°.  This  schist  bod} 
to  judge  from  the  appearance  of  the  old  workings  and  from  th 
results  shown  by  the  slope  now  being  sunk,  was  the  foot  wall  of  th 
ore  body.  The  foot-wall  schist  contains  much  disseminated  pyriti 
On  the  east  side  of  the  pit  the  hanging  wall,  a  schist  colored  deep  re 
along  its  outcrop,  is  shown.  This  dips  southeast  at  an  angle  of  aboi 
20°,  and  this  flattening  of  the  dip  toward  the  east  is  corroborated  b1 
profiles  of  the  mine  workings.     The  ore  body,  at  first  worked  as 
