MONONGAHELA FORMATION 



51 



the weather, and the surface for the most part is gently rolling, so that 

 natural exposures are comparatively rare. 



On the Pennsylvania railroad, about 8 miles south from the Kis- 

 kiminetis river, some cuts give opportunity for approximate measure- 

 ment ; two imperfect sections were obtained, one at a mile and a half, 

 the other at 5% miles north from the railroad, and Mr Piatt gives a 

 measurement in Indiana county at a short distance north from the river. 

 These may be compared. 



Feet 



1. Sandstone 



2. Coal bed 



3. Sandy shale 



4. Limestone 



5. Interval 



6. Coal bed 



7. Shales 30 



8. Limestone 1 



9. Clay, concealed, and 



sandstone 40 



10. Coal 



11. Shale 7 



12. Coal 



13. Limestone 1 



14. Shales 35 



15. Coal bed 



16. Clay, calcareous shale... 4 



17. Interval 80 



18. Pittsburg coal 9 



There is an error in the first measurement, and the interval from Number 

 8 to the Pittsburg is 161 feet; in the second it is 120; in the third the 

 Lower Sewickley coal bed is but 66, and in the fourth only 44 feet above 

 the Pittsburg. The highest coal bed, shown nowhere in the vicinity of 

 the first two measurements, underlies a massive sandstone and seems 

 to be at the Waynesburg horizon ; so that the Monongahela appears to lose 

 about 100 feet of thickness in 10 miles. This is in accord with condi- 

 tions farther west along the northern outcrop. 



Six miles south from the Pennsylvania railroad the interval, Waynes- 

 burg to Pittsburg, by barometer without regard to the dip, is 280 feet. 

 The higher coal bed is triple, 4 feet thick, with 3 feet of worthless coal, 

 and is separated by 25 feet of sandy shale from the "Waynesburg lime- 

 stone below. The Benwood limestone, practically absent on the railroad, 

 is thick at 8 miles south, where it is 25 feet above the Lower Sewickley, 

 which is about 4 feet thick. The Eedstone horizon shows only black 



dies 



Feet 



Feet Inches Feet 

 Not measured Not measured 





Blossom 



Blossom 





15 







15 





5 







Fragments 



Blossom 



-, 







30 



[75 







60 



6 Fragments 



















8 





Blossom 



Blossom 





 10 



70 



5 



> 





6 





1 



6 









8^ 



Blossom 



^ 





.44 



6 

 



50 



>- 



Blossom 



60 

 Blossom 



7 ■ '. 



