366  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
cline  to  the  vertical  zone  on  the  northwest  is  25°,  while  along  the 
Davis  Creek  section  the  dip  is  first  nearly  vertical  at  the  crest,  but  in 
a  short  distance  decreases  to  20°,  as  determined  by  observations  on 
the  surface  and  in  the  mines.  Nearer  the  vertical  or  steeply  inclined 
zone  to  the  west  the  western  dip  decreases  to  10°,  from  which  it 
changes  abruptly  to  60°  or  more.  At  a  cut  on  the  Louisville  and 
Nashville  Railroad,  a  short  distance  east  of  the  bridge  across  Davis 
Creek  east  of  Milldale,  this  change  of  dip  can  be  observed,  and  the 
same  change  can  be  seen  in  the  road  from  Adger  to  Kazburg  about  1-J 
miles  west  of  the  former  place.  Southwestward  from  the  Louisville 
and  Nashville  Railroad  bridge  across  Davis  Creek  east  of  Milldale 
the  dip  seems  to  diminish  in  the  line  of  the  western  vertical  zone. 
It  is  comparatively  light  along  the  headwaters  of  Texas  Creek,  and  on 
the  Middle  Fork  of  Hurricane  Creek  the  only  vertical  or  highly 
inclined  rocks  are  those  along  the  axis  of  the  anticline.  The  latter 
zone  of  vertical  rocks  extends  southwestward  through  Dudley,  and  in 
that  vicinity  nearly  the  whole  thickness  of  the  Coal  Measure  rocks 
outcrops  along  a  strip  not  over  one-half  mile  in  width.  The  south- 
eastern limit  of  these  rocks  and  of  the  Big  basin  is  approximately 
indicated  by  occasional  outcrops  of  vertical  sandstone  from  Dudley 
southwestward  to  Big  Sandy  Creek  about  2  miles  east  of  Pearl. 
Southwest  of  this  point  there  are  no  further  exposures  of  Carbon- 
iferous rocks. 
The  Little  basin  is  a  canoe-shaped  trough  extending  from  the 
vicinity  of  Union  Church  to  a  point  2  miles  north  of  McAdory.  Its 
northwestern  limit  has  already  been  defined;  its  southeastern  limit 
is  the  vertical  or  overturned  sandstone  of  Rock  Mountain.  From  the 
lateral  margins  of  the  basin  the  rocks  dip  at  angles  of  from  20°  to 
15°,  the  dip  gradually  decreasing  toward  the  center.  In  the  north- 
eastern end  the  rocks  of  the  central  part  are  thrown  into  a  number  of 
minor  rolls,  and  in  the  Johns  and  Adger  mines  an  anticline  of  consid- 
erable magnitude  was  discovered  running  parallel  to  the  longer  axis 
of  the  basin.  This  anticline  is  highest  at  Adger  and  decreases  south- 
westward,  appearing  as  a  low  fold  at  Johns  and  not  extending  as  far 
as  Belle  Sumpter.  Along  the  Louisville  and  Nashville  Railroad, 
crossing  the  basin  along  Davis  Creek,  the  rocks  are  practically  flat 
from  Jeebi  to  Wawah,  and  rise  from  either  place  at  first  gently  and 
then  more  steeply  to  the  margins  of  the  basin.  The  structure  of  the 
southern  end  of  the  basin  appears  to  be  rather  complicated,  and  its 
description  will  not  be  attempted  here. 
Besides  the  structures  already  described  the  field  is  more  or  less 
affected  by  faults.  Those  detected  run  in  a  general  way  at  right 
angles  to  the  southeastern  margin  of  the  basin.  Faulting  was 
observed  at  a  number  of  points.     A   fault  crosses  North  Fork  of 
