FELDSPAR  AND  QUARTZ  DEPOSITS  OF  SOUTH- 
EASTERN NEW    YORK 
By  Edson  S.  Bastin. 
INTRODUCTION. 
The  feldspar  and  quartz  deposits  near  Bedford  village,  in  West- 
chester Countv,  X.  V.,  were  visited  by  the  writer  In  January,  1907. 
These  deposits  have  been  described  briefly  in  the  reports  of  the  New 
York  State  Museum a  and  from  thai  description  a  part  of  the  material 
for  this  report  has  been  obtained. 
The  quarries  here  described  are  located  near  Bedford  village  and  2 
miles  to  the  south  in  the  town  of  North  Castle.  They  can  be  reached 
by  a  6  to  X  mile  drive  from  Mount  Kisco,  a  station  on  the  Harlem 
division  of  the  New  York  Central  Railroad,  38  miles  north  of  New 
Voir  City. 
GEOLOGIC    RELATIONS. 
The  feldspar  and  quartz  of  these  quarries  occur  as  constituents  of  a 
class  of  rocks  known  to  the  geologist  as  pegmatites.  In  their  mineral 
composition  these  rocks  are  closely  allied  to  granites,  the  principal 
constituents  in  both  being  feldspar,  quartz,  and  mica.  The  grain  of 
the  pegmatites,  however,  is  as  a  rule  exceedingly  coarse  and  the  tex- 
ture very  irregular,  as  brought  out  in  another  part  of  this  bulletin 
(pp.  385-386)  in  the  description  of  the  pegmatites  of  Maine. 
The  rocks  of  the  region  are  a  mica  schist  (the  Hudson  schist)  and 
scattered  masses  of  crystalline  limestone  (the  Stockbridge  dolomite). 
Both  of  these  rocks  have  been  shown  to  be  of  sedimentary  origin,) 
though  extensively  altered  by  met  amorphic  action.  They  now  lie  in 
a  series  of  closely  compressed  folds,  whose  general  trend  in  the  region 
here  described  is  northeast  and  southwest.  The  Hudson  schist  has 
been  shown  to  be  of  Ordovician  age;  the  Stockbridge  dolomite  is  in 
part  Ordovician  and  in  part  Cambrian. 
In  the  vicinity  of  the  feldspar  and  quartz  quarries  and  along  much 
of  the  road  between  Bedford  village  and  Mount  Kisco  the  Hudson 
a  Bull.  X.  V.  State  Museum  No.  102,  1905,  p.  69. 
394 
