412  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,    1903.  [bull.225. 
The  Philadelphia  Company  has  a  16-inch  line  extending  across  the 
county  from  northeast  to  southwest;  a  10-inch  line  from  Blacksville 
(o  Waynesburg;  two  or  three  lines  to  the  Waynesburg  field,  and  a 
second  Hi-inch  line  from  Waynesburg  northeast  toward  Pittsburg. 
The  People's  Natural  Gas  Company  has  lately  completed  a  20- inch 
line  which  enters  Greene  County  at  Dent,  passes  4  miles  east  of 
Waynesburg,  and  goes  out  of  the  count}^  near  Zollarsville. 
The  Manufacturers'  Light  and  Heat  Company  takes  gas  from  the 
held  south  of  Waynesburg  through  a  16-inch  line,  and  the  Fort  Pitt 
Gas  Company  has  a  12-inch  line  which  crosses  the  county  from  a 
point  -ti  miles  east  of  Blacksville  to  Zollarsville,  and  carries  gas  to 
Pittsburg. 
SUMMARY. 
From  the  above  statements  it  is  seen  that  in  various  parts  of  the 
territory — 
1 .  Oil  is  contained  in  the  sandstones  of  the  Lower  Barren  measures, 
or  Conemaugh  formation,  and  in  the  Big  Injun  and  Gantz  sands. 
2.  Gas  is  found  in  commercially  important  quantities  in  the  Big 
Injun,  Gantz,  Fifty-foot,  Fifth,  and  Bayard  sands. 
3.  Salt  water  from  the  Salt  sand,  Big  Injun,  and  Bayard  has  flooded 
some  holes. 
It  is  shown  also  that  the  principal  accumulations  of  gas  are  either  on 
the  crests  of  the  anticlinal  folds  or  on  the  steep  flanks.  The  oil  pools 
are  located  at  points  on  the  flank  of  an  anticline  where  the  dip  is  consid- 
erably flattened  or  at  a  low  point  on  the  crest  of  an  arch.  Wells  drilled 
in  the  bottoms  of  the  synclinal  basins  have,  for  the  most  part,  been 
unproductive.  These  relations  of  the  accumulations  of  gas,  oil,  and 
water  to  geologic  structure  are  in  accord  with  the  anticlinal  theory 
and  show  the  value  of  an  accurate  determination  of  structure  in  the 
location  and  extension  of  oil  and  gas  fields. 
