System 



Kind of Rock 



Dunkard 



sandstone, 



limestone 



and coal 



Monongahela 

 shale, sand- 

 stone, lime- 

 stone and coal 



Co /tenia ugh 



shale, 



sandstone 



and little 



coal 



Allegheny 

 shale, sand- 

 stone and coal 



PoUsmUe 



sandstone 

 and some coal 



Mauch Chunk 



shale, sandstone 



and limestone 



