96 THE DEVONIAN AND CARBONIFEROUS. [bull. 80. 



(3) Lower or Alleghany River series, consisting of shales, coal beds, limestone, and. 



ores, and down to the Conglomerate, No. XII. 



(4) Ore beds of XI ; limestones of XI. 



(5) Catskill rocks, No. X, or Catskill gray sandstone. 



(6) Chemung rocks No. VIII. 



The means of correlation and identification were the "Pittsburg 

 coal," distinguishing the base of the Upper Coal Measures, the 

 "Mahoning sandstone," which is described as " the great key rock of 

 the bituminous coal field in Pennsylvania, Ohio, West Virginia, and 

 Kentucky. It was first best studied on the Mahoning River, in Jeffer- 

 son County, and hence its name." 1 



This marks the base of the "Lower Barren Measures" and it puts 

 on locally a thousand varying aspects, being coarse, pebbly, and 

 massive, and again fine-graiued, thin-bedded, and shaly." And at the 

 base of the lower series is the "Conglomerate No. XII," which presents 

 similar variations. It is the "Serai" Conglomerate of the first survey. 



In 1877 Mr. Piatt 2 published the following " Scheme of the measures" 

 which " would be met with could a well be bored near Waynesburg, or 

 on the highest geological land in Greene County: 3 



1. The Monongahela River system : 



(a) Greene County group of Upper Barren Measures. 



(b) Washington County group of Upper Barren Measures. 



(c) Upper Productive Coal Measures. 



2. The Alleghany River system : 



(a) Lower Barren Measures. 



(b) Mahoning sandstone. 



(c) Lower Productive Coal Measures. 



3. The Kanawha River system : 



(a) Pottsville Conglomerate . Lj, 



(b) Kanawha Coal Measures . S 



(c) Mauch Chunk red shale., /yj 



(d) Mountain limestone S 



4. The New River system (of Lesley, not of Fontaine) : 



(a) New River Coal Measures ) y 



(&) Pocono (Upper Catskill) sandstone . $ * 



4. The Devonian system : 



(a) Catskill Old Red sandstone, IX. 

 (6) Chemung sand and shales 



(c) Portage shales and sands 



( Genesee black shales. . . 



(d) Hamilton < Juniata Coal Measures. 



( Marcel] us black shales. 



(e) Upper Helderberg limestone 



5. Upper Silurian system : 



(a) Oriskany sandstone, etc., to the Archean. 



Four new names are noted in this list, "proposed by the present State 

 geologist of Pennsylvania," viz : 



Pottsville Conglomerate, for Rogers' " Serai," No. XII. 

 Mauch Chunk Red shale, for Rogers' " Umbral," No. IX. . 

 Kanaicha Coal Measures, for Fontaine's " New River " series. 

 Pocono sandstone, for Rogers' " Vespertine," No. X. 



1 Second Geol. Surv. of Pennsylvania, Rept. of Progress L. Special Report on the coke manufacture 

 of the Yougbiogheny River Valley in Fayette and Westmoreland Counties, 1875, 22. 



2 Geol. Survey of Pennsylvania, Rept. of Progress W: Report on Cambria County, by F. and W. G. 

 Piatt, pp. 194, 1877. 



'Ibid., p. xxin. 



Win. 



