MONONGAHELA FOKMATION 55 



of Monongaliela, known as Elders ridge, and north from the Kiski- 

 minetis river along the Armstrong-Indiana border, was studied by Mr 

 W. G. Piatt and, 25 years later, by Mr E. W. Stone. Another small 

 area remains in Westmoreland at 1 mile and the continuous body is 

 reached at 7 miles south from the Kiskiminetis. The first clear section 

 is at the Youghiogheny shaft near Irwin, 20 miles south from Elders 

 ridge ; at somewhat more than 4 miles north is a boring, and at 4 miles 

 farther north is another, very near the end of the continuous area. 

 These may be compared as follows : 



Feet Inches Feet Inches Feet Inches 



1. Uniontown coal bed 3 11 5 



2. Shale, limestone, sandstone. 106 72 7 50 8 



3. Coal bed 1 to 3 4 9 1 3 



4. Shale, limestone, sandstone. 50 67 6 70 



5. Pittsburg coal bed 11 2 15 6 Not measured 



Along the Pennsylyania railroad the Uniontown coal bed is about 160 

 feet above the Pittsburg and is above its limestone. In the first section 

 it is about 60 feet below the Waynesburg, which is exposed on the hill- 

 side and about 3 feet thick. The Benwood limestone is 15 feet thick 

 and 35 feet below the Uniontown limestone, so that it represents the 

 upper part of the mass. A hard sandstone, 25 feet thick, rests on the 

 middle coal bed along the railroad, while at 8 to 11 feet below that 

 coal is a limestone; this condition suggests reference of the coal bed to 

 the Lower Sewickley. The interval from the Uniontown to the Pitts- 

 burg decreases northwardly, being 158, 145, and 123 feet in the measure- 

 ments given, while one intermediate between the last two shows 131. 

 The coal beds of the section are present in Elders ridge, where they are 

 98 and 35 feet above the Pittsburg. An intermediate observation shows 

 the lower bed at 65 feet above the Pittsburg, marking the renewed de- 

 crease in that direction. No higher coal is recorded in northern West- 

 moreland, where, a record gives the overlying beds for 85 feet ; the high- 

 est is a limestone, 7 feet 6 inches, evidently the same with that seen in 

 Elders ridge at 83 feet above the Uniontown. The Fishpot and Union- 

 town limestones disappear northwardly, only the Benwood persisting in 

 Elders ridge. 



The Pittsburg retains its complex structure along the Pennsylvania 

 railroad, where one often finds the "rider'' coal of this, as in the Greens- 

 burg basin. In the Youghiogheny shaft this little coal is distributed in 

 fragments throughout 2 feet of sandstone. The roof division is as 

 variable here as elsewhere; at one pit it is 7 feet 4 inches thick, in nine 

 layers, with, in all, 3 feet 5 inches of coal, but in another less than a 



