Am.  Jour.  Pharm.  \ 
April,  1888.  j 
The  Origin  of  Petroleum. 
191 
that,  "  Under  the  names  of  petroleum  or  rock  oil  are  arranged  various 
mineral  oils,  which  are  observed  in  many  places  to  issue  from  the 
earth  in  considerable  abundance,  and  there  is  every  reason  to  suppose 
that  these  owe  their  origin  to  the  action  of  internal  heat  upon  beds  of 
coal,  as  they  are  usually  found  in  connection  with  such." 
One  of  the  earliest  advocates  of  the  organic  theory  appears  to  have 
been  Dr.  I.  S,  Newberry,  an  American,  who  in  1859  made  an  import- 
ant communication  on  petroleum,  in  which  he  states  that  the  precise 
process  by  which  petroleum  is  evolved  from  the  carbonaceous  matter 
contained  in  the  rocks  which  furnish  it,  is  not  yet  fully  known,  be- 
cause we  cannot,  in  ordinary  circumstances,  inspect  it.  We  may  infer, 
however,  that  it  is  a  distillation,  though  generally  performed  at  a  very 
low  temperature. 
Another  American,  Professor  S.  F.  Peckham,  in  his  elaborate  mono- 
graph on  petroleum,  published  in  connection  with  the  10th  Census  re- 
ports of  the  United  States  Government,  and  which  I  may  say  here  is 
the  most  perfect  and  exhaustive  work  on  the  subject  I  have  seen, 
treats  the  question  we  are  discussing  at  some  length,  and  states  that 
liis  researches,  extending  over  a  period  of  more  than  twenty  years, 
convince  him  that  all  bitumens  (including  petroleum)  have  in  their 
present  condition  been  deprived  of  vegetable  or  animal  organisms,  but 
the  manner  of  their  derivation  has  not  been  uniform. 
I  may  here  state  that  petroleum  has  been  found  in  all  geological 
strata,  from  the  Silurian  up  to  the  Tertiary ;  but  it  occurs  principally 
in  only  two  of  these  epochs,  namely,  the  Silurian  and  the  upper  divi- 
sion of  the  Tertiary  period. 
In  the  vast  petroleum  regions  of  Pennsylvania,  Ohio,  etc.,  petroleum 
is  found  saturating  heavy  beds  of  uncemented  sandstone.  Beneath 
this  sandstone  or  sands,  as  they  are  called,  are  shales  as  much  as  1600 
feet  in  thickness.  Professor  Peckham  says  no  one  can  examine  this 
strata  without  noticing  the  immense  quantity  of  fucoidal  remains  that 
it  contains. 
He  says  if,  however,  the  Devonian  shales  are  inadequate,  both  on  ac- 
count of  extent  and  supply,  to  account  for  the  production  of  the  vast 
supplies  of  petroleum,  we  may  descend  still  lower  in  the  geological 
series  to  the  Silurian  limestones  of  over  1200  feet  in  thickness,  con- 
taining geodes  or  cavities  filled  with  petroleum.  Too  little  is  known, 
he  says,  about  petroleum  to  enable  anyone  to  explain  all  the  phen- 
omena attending  its  occurrence  or  any  hypothesis,  but  it  seems  to  him 
