1881.] OOJ [Ashburner. 



the natural inference would be that a number of valuable workable beds 

 should be found here, out of the eight beds which these groups generallj' 

 embrace, and which have proved so productive in other portions of Penn- 

 sylvania. The fact is, however, that at St. Mary's only one coal bed has 

 as yet been found* of sufficient purity and thicknessf to be profitably 

 mined over any considerable area. This bed is the Dagus or Lower Kit- 

 tanning coal bed. 



But besides this bed the St. Mary's section contains representatives of 

 the Upper and Middle Kittanning, the Clarion and Mercer coal beds ; and 

 the ground at the Patton Hill near the west mine of the St. Mary's Coal 

 Company is high enough to contain a very small area of the Freeport 

 Lower coal, although it has not been discovered. 



The following is a general section of the coal measures in the vicinity of 

 St. Mary's, compiled from facts obtained within a radius of one and a half 

 miles of the Philadelphia and Erie railroad station. For the sake of com- 

 pleteness I have added to this section the record of the drill hole of the St. 

 Mary's Oil Company, making in all nearly a half mile of vertical thickness 

 of rocks whose character is actually known : 



Elk County Section ; at St. Mary's. 



1. Gray sandstone, shale and slate 67 



3. Coal, Kittanning Upper. ..' 3' 



3. Sandy shale and slate 33' 



4. Coal, Kittanning Middle. 1' Q" 



5. Sandstone and shale 55' 



6. Coal, Dagus, Kittanning Lower 3' 



7. FireclayJ 3' 



8. Shale 17' 



9. Coal 1' 4" 



10. Sandstone and shale 10' 



11. Limestone and shale, Clermont, Ferriferous 10' 



13. Shale 13' 



13. Coal 5" 



14. Shale 16' 



15. Coal, Clermont, Clarion 2' 



16. Sandstone and shale, Johnson kun S. S 32' 



17. Coal, Alton Upper 2' 7" 



18. Shale 18' 



*The Clermont or Clarion bed has been worked to a limited extent on the 

 Monastery lands east of Silver creek, about three-quarters of a mile north- 

 west of the St. Mary's railroad station. 



tThe degree of purity and extent of thickness necessary to constitute a work- 

 able, marketable coal bed, are purely arbitrary, and their values are dependent 

 upon commercial questions. 



X A fireclay bed invariably forms the floor of all our bituminous coal seams. 

 They have not been noted in the section except where their tliickuess has been 

 determined; inmost cases they have been included in the rock interval be- 

 neath each coal bed, 



PROC. AMER, pgiLOs. soc. XIX. 108. 2q, printed may 3, 1881. 



