KCKKIi.  J 
LIMONITE    OF    NEW     VOKK    AND    NEW     KNCLANl). 
339 
large  disintegrated  mass  mixed  with  clay,  thins  down  to  about  ^0  feet 
where  it  passes  under  the  hanging  wall. 
Manganese  ores  occur  apparently  mostly  in  the  lower  levels  of  the 
mine.  Iron  carbonate  occurs  at  the  north  end  of  the  mine  at  a  rather 
high  level  in  connection  with  masses  of  limestone.  A  few  hundred 
feet  west  of  the  pit  a  thin  brecciated  band  of  limestone  appears  in  the 
schist.     Analyses  of  the  ores  of  this  group  of  mines  follow  : 
Analyses  of  iron  ores  of  mines  at  Orehill,  near  Lakeville,  Conn. 
1. 
2. 
3. 
4. 
5. 
6. 
7. 
Metallic  iren 
Phosphorus 
Phosphorus    in   100 
parts  iron 
35.10 
.128 
.364 
40. 03 
.113 
.282 
44.04 
.100 
.227 
44.38 
.103 
.232 
48.02 
.120 
.250 
50. 12 
.196 
.393 
44.80 
.162 
.362 
In  the  description  of  this  group  of  mines  in  the  Tenth  Census 
Report,  volume  15,  pages  84-85,  it  is  stated  that  a  fault  occurs  in  the  ore 
body  in  one  of  the  pits.  This  can  not  be  determined  at  present,  and 
toiii  the  description  and  its  accompanying  figure  it  seems  probable 
that  it  was  merely  a  slip  in  surface  material  and  not  in  any  way  con- 
nected with  the  origin  of  the  ore  body. 
Mount  Riga  mine. — The  Mount  Riga  mine  is  located  one-half  mile 
east  of  Mount  Riga  station,  N.  Y.  It  is  a  pit  about  100  feet  by  300 
feet  in  area  and  is  now  filled  with  water.  No  solid  rock  is  shown 
near  it,  but  it  is  probably  located  not  far  from  a  contact  between  lime- 
tone  and  schist.  A  partial  analysis  of  its  ore  is  given  in  the  Tenth 
Census  Report,  volume  15,  page  134 : 
Analysis  of  iron  ore  from  Mount  Riga  mine,  Dutchess  County,  N.  Y. 
Per  cent. 
Metallic  iron 41.58 
Phosphorus  .611 
Phosphorus  in  loo  parts  iron 1.470 
Manhattan  mine. — The  Manhattan  mine,  located  immediately  west 
)f  the  railroad  at  Sharon  station,  N.  Y.,  is  of  interest  to  mining 
engineers  because  of  the  detailed  expense  accounts  published  by  Mr. 
l<ewis  in  the  Transactions  of  the  American  Institute  of  Mining 
Engineers.  Smock  states  that  limestone  occurs  in  the  pit,  but  none 
s  now  visible.  Numerous  limestone  outcrops  occur  a  short  distance 
south  of  the  mine,  however,  striking  X.  t0°  E.  and  dipping  30°  SE. 
There  can  be  no  reasonable  doubt  that  the  ore  body  occurred  entirely 
n  or  on  the  limestone,  like  that  of  the  Leet  mine,  above  described. 
So  schist  or  quartzite  could  have  been  concerned  in  the  localization 
