260 
CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1905. 
ences  to  numbers  are  to  those  of  the  Kentucky  Geological  Survey .«  The  Pottsville  ou 
crops  generally  all  over  the  western  and  southern  portions  of  the  quadrangle,  running  und< 
drainage  toward  the  syncline  and  forming  most  or  all  of  the  hills  along  the  western  ar 
southern  edges  of  the  quadrangle.  It  is  prevailingly  sandy.  This  group  of  rocks  cor 
prises  all  the  coals  up  to  and  including  coal  No.  4,  besides  valuable  beds  of  fire  clay.  Tl 
base  of  the  formation  is  easily  determined,  for  it  rests  on  top  of  the  Greenbrier  (Lower  Ca 
boniferous)  limestone.  Its  top  is  composed  of  the  usually  massive  Homewood  sandston 
which  lies  some  feet  above  coal  No.  4  or  rests  directly  on  this  coal  bed.  Certain  of  the  co 
beds  of  this  group  of  rocks  arc  very  important  on  the  edges  of  the  basin  in  the  southeaster 
Fig.  10. 
Sketch  map  of  northeastern  Kentucky  and  portions  of  adjacent  Staccs. 
and  western  parts  of  the  quadrangle.  It  is  possible  that  rocks  still  lower  in  the  Pottsvil 
than  the  basal  Pottsville  beds  along  the  western  side  of  the  basin  occur  in  the  Levisa  Foi 
district,  but  the  evidence  on  which  this  statement  is  based  depends  on  fossil  plants  collects 
by  Dr.  David  White,  and  these  have  not  been  studied  closely  enough  up  to  the  present  tin 
to  warrant  a  positive  statement  on  this  point. 
Above  these  lower  sandy  formations  occurs  the  group  of  rocks  corresponding  to  tl 
Allegheny  formation  of  Pennsylvania  and  containing  coals  No.  5  to  No.  9.  It  consis 
of  alternating  beds  of  sandstone  and  shale,  with  occasional  thin  beds  of  limestone,  in 
ore,  and  fire  clay.     This  group  includes  the  celebrated  Ashland  or  Coalton  coal  and  tl 
a  Crandall,  A.  R.   Report  on  the  Geology  of  Greenup,  Carter,  and  Boyd  counties,  and  a  part  of  Lai 
rence;  Geol.  Survey  Kentucky,  Report  on  the  Eastern  Coal  Field,  vol.  C,  1884,  pp.  1-78. 
