192 
The  Origin  of  Petroleum. 
Am.  Jour.  Phaam. 
April,  1888. 
that  the  different  varieties  are  the  product  of  fractional  distillation, 
and  that  one  of  the  strongest  proofs  of  this  hypothesis  is  found  in  the 
large  content  of  paraffin  wax  in  the  Bradford  oil  (Penn.)  wells  under 
,  the  enormous  pressure  to  which  it  is  subjected.  If,  he  says,  the  or- 
ganic theory,  which  embraces  all  the  facts  that  have  thus  far  come  with- 
in our  knowledge,  really  represents  the  operations  of  nature,  then  we 
must  seek  the  evidence  of  heat  action  at  a  depth  far  below  the  unal- 
tered rocks  in  which  the  petroleum  is  now  stored.  We  ought  to  ex- 
pect to  find  the  coal  in  its  normal  condition.  We  should  not  expect 
to  find  the  carbonized  remains  of  organisms  in  the  rocks  containing 
petroleum.  If  petroleum  was  the  product  of  a  purely  chemical  pro- 
cess we  should  expect  to  find  a  general  uniformity  in  its  character 
wherever  it  was  found,  whereas  Professor  Peckham  says,  we  find  that 
petroleum  from  the  Silurian  strata  containing  mixtures  of  hydrocar- 
bons only,  without  any  trace  of  nitrogen,  and  petroleum  from  other 
parts  of  the  world  from  tertiary  strata  containing  nitrogen.  This 
fact  lends  additional  weight  to  the  theory  of  organic  origin,  as  the 
petroleum  from  the  Silurian  formations  corresponds  in  its  composition 
with  a  natural  distillation  of  the  simple  animal  and  vegetable  organ- 
isms that  flourished  in  that  remote  period  or  epoch,  and  the  Tertiary^ 
petroleums  containing  nitrogen  prove  their  being  the  result  of  the  de- 
composition of  more  highly  organized  beings,  such  as  flourished  at  a 
later  epoch. 
The  advocates  of  that  side  of  the  organic  theory  which  regards 
petroleum  as  indigenous  to  the  rocks  in  which  we  find  it,  are  mainly 
Professor  Leslie  and  Dr.  Sterry  Hunt,  both  well-known  geologists. 
They  base  their  views  on  their  observations  in  West  Virginia,  Canada 
and  Kentucky.  They  find  the  Silurian  limestones  in  those  districts 
contain  fossil  corals  and  geodes,  in  all  of  which  the  oil  appears  to  be 
hermetically  sealed  until  the  mass  is  broken.  They  think  that  these 
were  probably  deposited  in  a  deep  sea  at  a  somewhat  high  temperature 
in  which  vast  quantities  of  sea  animals  perished  and  became  buried ; 
they  therefore  consider  it  most  strictly  in  accord  with  observed  facts 
to  assume  that  in  whatever  manner  the  oil  may  have  been  produced 
from  the  original  animal  organisms  it.  is  indigenous  to  the  rocks  in 
which  it  is  now  found.  The  above  statement,  I  tliink,  will  prove  suf- 
ficient for  my  purpose,  namely,  to  place  before  you  the  principal  views 
of  the  advocate  of  the  organic  theory,  and  if  I  may  trespass  a  little 
longer  on  your  patience  we  will  now  return  to  a  consideration  of 
