314  Notes  on  American  Asphaltum.  {kv'A\^Jm^ 
abound.  There  is  little  room  for  doubt  that  in  each  instance  the  fis- 
sures which  contain  the  asphalt  have  afforded  convenient  reservoirs 
into  which  petroleum  has  flowed,  and  from  which  all  the  lighter  parts 
have  been  removed  by  evaporation.  A  large  number  of  similar  de- 
posits, though  of  less  magnitude,  are  known  to  me,  all  presenting  the 
same  general  features.  Among  these  I  may  mention  a  nearly  verti- 
cal bed  in  the  mountains  west  of  Denver,  in  Colorado.  This  is  a  fis- 
sure filled  with  an  asphalt  which  I  submitted  to  Prof.  Henry  Wurtz 
for  examination,  and  which  he  has  shown  to  be  not  essentially  differ- 
ent from  Grahamite.  On  the  banks  of  the  Arkansas,  south  from 
Denver  City,  a  number  of  smaller  fissures,  cutting  cretaceous  rocks, 
are  filled  with  a  similar  asphaltic  mineral.  In  the  great  Devonian 
black  shale  of  Ohio  and  Kentucky  (Huron  Shale),  fissures  cutting 
across  the  bedding  of  the  formation  filled  with  Albertite,  occur  near 
Avon  Point,  Lorain  Co.,  Ohio,  and  Liberty,  Casey  Co.,  Kentucky. 
Petroleum  flows  from  this  formation  nearly  everywhere  along  its  line 
of  outcrop.  The  asphalt  from  all  the  localities  I  have  cited  is  hard, 
bright  and  brittle,  and  seems  to  be  the  product  of  very  long  continued 
and  complete  spontaneous  distillation  and  oxidation. 
In  southern  California,  western  Canada,  central  Kentucky  and 
Chicago,  &c,  asphaltum  may  be  seen  in  the  process  of  formation  from 
petroleum.  In  Enniskillen,  Canada,  an  abundant  flow  of  dark  and 
heavy  oil  has  produced  large  accumulations  of  more  or  less  perfectly 
formed  asphalt  at  the  surface.  These  are  locally  known  as  gum  beds. 
They  attracted  the  attention  of  Mr.  Williams  in  1860,  when  the  dis- 
tillation of  oil  from  cannel  coal,  bituminous  shales,  etc.,  was  expand- 
ing into  an  important  industry,  and  he  established  an  oil  distillery 
there  for  the  use  of  this  material.  On  cutting  through  the  crust  of 
solidified  asphalt,  semi-fluid  and  finally  fluid  petroleum  was  met  with, 
afterwards  these  oil  springs  yielded  immense  quantities  of  petroleum. 
In  Butler  Co.,  Kentucky,  the  central  member  of  the  lower  carbon- 
iferous group,  is  saturated  with  petroleum.  This  flows  out  from  the 
cut  edges  of  the  formation  in  the  valley  of  Green  river  and  its  branches, 
forming  sheets  of  mineral  tar  and  ultimately  asphaltum,  which  cover 
the  exposed  surfaces  of  the  rock.  The  quantity  of  asphaltic  material 
in  this  vicinity  is  large,  and  it  may  some  time  be  utilized  for  road 
making  in  the  same  manner  as  the  Syssel  asphalt. 
In  southern  California,' the  accumulations  of  asphalt  on  the  coast 
of  Santa  Barbara,  San  Luis  Obispo,  &c,  have  attracted  the  notice  of 
