HISTORY  OF  PETROLEUM  OR  ROCK  OIL. 
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Higher  still  in  the  series,  at  the  base  of  the  Hamilton  group, 
occur  what  in  New  York  have  been  called  the  Marcellus  shales; 
these  enclose  septaria  or  concretionary  nodules,  which  contain 
petroleum,  while  at  the  summit  of  the  same  group  similar  con- 
cretions, holding  petroleum,  are  again  met  with.  The  sand- 
stones of  the  Portage  and  Chemung  group,  in  New  York,  are  in 
many  places  highly  bituminous  to  the  smell,  and  often  contain 
cavities  filled  with  petroleum,  and  in  some  places  seams  of  in- 
durated bitumen.  A  calcareous  sandstone  from  this  formation, 
at  Laona,  near  Fredonia,  in  Chatauque  County,  contains  more 
than  two  per  cent,  of  bituminous  matter.  At  Rockville,  in  Al- 
leghany County,  according  to  Mr.  Hall,  the  same  sandstones 
are  highly  bituminous,  and  give  out  a  strong  odor  when  handled, 
and  in  the  counties  of  Erie,  Seneca,  and  Cataraugus,  abundant 
oil  springs  rise  from  the  sandstones,  and  have  been  known  to 
the  Seneca  Indians  from  ancient  times.  In  the  northern  part 
of  Ohio,  according  to  Dr.  Newberry,  petroleum  is  found  to  ex- 
ude, in  greater  or  less  quantity,  from  these  sandstones  wherever 
they  are  exposed,  and  the  oil  wells  of  Pennsylvania  and  Ohio 
are  sunk  in  these  Devonian  sandstones,  often  through  the  over- 
lying carboniferous  conglomerate,  and  in  some  cases  apparently, 
according  to  Newberry,  through  the  sandstones  themselves, 
which  are  supposed  by  him  to  be  only  reservoirs  in  which  the 
oil  accumulates  as  it  rises  through  fissures  from  a  deeper  source, 
in  proof  of  which  he  mentions  that,  in  boring  wells  near  to  each 
other,  the  most  abundant  flow  of  oil  is  met  with  at  variable  depths. 
In  some  instances  the  petroleum  appears  to  filter  slowly  into  the 
wells  from  the  porous  strata  around,  which  are  saturated  with  it, 
while  at  other  times  the  bore  seems  to  strike  upon  a  fissure 
communicating  with  a  reservoir  which  furnishes  at  once  great 
volumes  of  oil.  An  interesting  fact  is  mentioned  in  this  con- 
nection by  Mr.  Hall.  In  the  town  of  Freedom,  Cataraugus 
County,  New  York,  is  a  spring  which  had  long  been  known  to 
furnish  considerable  quantities  of  petroleum.  On  making  an 
excavation  about  six  yards  distant,  to  the  depth  of  fourteen  feet, 
a  copious  spring  of  petroleum  arose,  and  for  some  time  afforded 
large  quantities  of  oil,  after  which  the  supply  diminished  in  both 
the  old  and  new  springs,  so  that  it  is  now  less  than  at  the  first 
settlement  of  the  country.    Notwithstanding  its  general  distri- 
