£02  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull.225. 
wells  which  reach  this  depth.  The  Gordon  sand  is  named  from  the 
farm  near  Washington,  Washington  County,  where  it  was  discovered 
in  August,  1885. 
Fourth  sand.-  Another  sand  which  produces  only  a  small  amount  of 
gas  is  the  Fourth  sand.  Its  top  is  at  an  average  distance  of  2,230 
feet  below  the  Pittsburg  coal,  and  its  thickness  is  variously  regarded 
as  from  7  to  70  feet.  The  presence  of  the  Fourth  sand  is  noted  almost 
as  frequently  as  that  of  the  Gordon,  which  indicates  something  of  its 
persistence. 
Fifth  sand. — The  great  gas  producers  of  the  group  of  sands  which 
are  known  in  Greene  County  are  the  Fifth  and  Bayard  sands.  By  far 
the  larger  number  of  wells  in  Greene  County,  excepting  those  in 
Dunkard  and  Morris  townships,  are  sunk  to  one  or  both  of  these  hori- 
zons. The  Fifth  sand  is  at  an  average  distance  of  2,313  feet  below 
the  Pittsburg  coal,  and,  according  to  the  various  records,  ranges  in 
thickness  from  10  to  65  feet.  A  study  of  the  average  distances  from 
the  Pittsburg  coal  to  the  Fifth  sand  shows  that  the  distance-between 
the  least  and  greatest  intervals  is  barely  more  than  100  feet,  while  the 
average  distances  in  five  townships  vary  only  23  feet.  In  other  words, 
the  Fifth  sand  seems  to  lie  very  nearly  parallel  with  the  Pittsburg 
coal. 
Bayard  sand. — Gas  is  found  more  frequently  in  paying  quantities 
in  the  Bayard  than  in  any  other  sand  in  this  field.  The  distance  from 
the  top  of  the  Fifth  to  the  top  of  the  Bayard  sand  in  00  wells 
averages  120  feet.  The  depths  at  which  the  drill  has  found  it  below 
the  Pittsburg  coal  are  from  2,388  feet  to  2,161  feet,  averaging  2,133 
feet.  The  thickness  of  the  Ba}^ard  sand  seems  to  vary  considerably. 
A  few  wells,  which  have  passed  completely  through  it,  give  3  to  12 
feet  as  the  thickness,  while  other  wells,  which  stopped  when  the  gas 
was  struck  and  did  not  go  to  the  bottom  of  the  sand,  have  noted  20  to 
30  feet.  The  Bayard  is  also  known  by  some  drillers  as  the  Sixth  sand. 
The  name  Bayard  was  introduced  in  gas-sand  nomenclature  in  February, 
1895,  when  a  successful  well  was  completed  on  the  Thomas  Bayard 
farm,  Whiteley  Township,  Greene  County. 
iLlizaheth  sand.  — This  term  is  applied  to  a  sand  which  carries  some 
gas,  and  is  found  at  depths  ranging  from  100  to  175  feet  below  the  top 
of  the  Bayard.  Its  thickness,  as  recorded  in  three  wells,  is  not  more 
than  7  feet.  Probably  the  number  of  holes  sunk  to  this  sand  in  the 
eastern  half  of  Greene  County  is  less  than  10. 
GEOLOGIC    STKUCTURE. 
The  structural  features  of  the  eastern  half  of  Greene  County  have 
the  northeast-southwest  strike  which  is  characteristic  of  the  whole 
Appalachian   province.     These  are  shown    by   contour  lines  on  the 
