410  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
Pattersons  Mill  northward  is  only  a  little  greater  than  the  upward 
slope  of  the  coal  in  that  direction.  The  coal  shows  in  natural  jont- 
crop  at  Pattersons  Mill,  and  3  miles  up  the  valley  of  North  Fork 
toward  Eldersville  it  is  only  70  feet  below  the  surface.  From  the 
point  of  outcrop  near  Pattersons  Mill  an  entry  driven  about  N.  30° 
E.  would  have  sufficient  grade  to  drain  itself,  and  the  coal  could  be 
delivered  to  the  mouth  of  the  mine  by  gravity.  With  a  branch  rail- 
road up  the  main  Pattersons  Mill  Creek  shafts  could  be  sunk  along 
this  line  at  intervals  of  a  mile  or  so,  and  the  whole  system  could  be 
connected  by  underground  workings,  thereby  permitting  natural 
drainage  of  the  entire  area  through  the  first  opening,  near  Patter- 
sons Mill.  This  system  of  development  would  permit  the  mining  of 
a  large  body  of  coal  to  the  north  and  northeast  and  its  delivery  to 
the  various  shafts  in  question  by  short  down-grade  hauls. 
