

wiluamr.1 LESLEY, ANDREWS. 91 



The following scheme will show the old problem and its recent probable solution : 



In Ohio. 



Conglomerate... 

 Cuyahoga shale 

 Bereagrit ... 



Bedford shales 



Cleveland shales 



Erie shales 



Huron shales ... 

 Corniferous 



In northwestern 

 Pennsylvania. 



Second Mount a i n 

 saudstoue 



Oil sands 



In New York. 



In middle 



Pennsylvania. 



Conglomerate 



Old Red sandstone 

 (fish). 



Chemung 



Portage 



Hamilton 



Upper Helderberg . 



Serai Cong., xn. 

 Umbral, xi. 

 Vespertine, x. 



Ponent, ix. 



Vergent, vin. 

 Vergent. VIII. 

 Cadent, vin. 

 PostMedidial, vm. 



Tlie author states in a foot-note that lie does not adopt " the general 

 term Waverly sandstone formation of the Ohio Reports because of the 

 controversies to which it has given rise." Also, that " Erie shales" 

 should stand opposite both Chemung and Portage. 



In a letter to the editor of the Journal, 1 dated June 26, 1875, Prof. 

 Lesley speaks of Mr. Ash burner's discovery of what he calls' 4 baby 

 coal beds" in No. X, Upper or White Catskill, Rogers's Vespertine, in 

 Huntingdon County, Pennsylvania, and considers it of great impor- 

 tance to American geology, as it explains the presence of the two coal 

 beds on the face of the Alleghany Mountains and the fourteen small 

 coal beds counted by Prof. Lesley years before, west of the Peak 

 Mountain, in Wythe County, Virginia. 



E. B. Andrews 2 compares the Ohio and West Virginia coal fields. 



In this comparison the author takes the Pittsburg seam of coal as 

 the base of measurement. This seam occupies the northern portion of 

 the Alleghany coal field, and extends through Pennsylvania, Ohio, and 

 West Virginia. From its outcrop to the base of the productive Coal 

 Measures the intervals remain quite uniform. In Ohio Dr. New- 

 berry's measurement is from 700 to 800 feet and Prof. H. D. Rogers's 

 from GOO to 700 feet. But in the southern part of West Virginia the 

 interval is much greater. Prof. Fontaine estimates 3,100 feet as the 

 total thickness from the horizon of the Pittsburg seam to the base of 

 the productive Coal Measures. This does not include the shales and 

 the adjacent Lewisburg limestone, which are probably local. Hence 

 we find about 2,400 feet more of Coal Measures in Virginia than in 

 Ohio and Pennsylvania, and hence in West Virginia the series of pro- 

 ductive Coal Measures make up a great geosynclinal, which is probably 

 due to continental foldiug. The various coal seams, separated by 

 small layers of shale, indicate that it was subject to alternate depres- 

 sion and elevation. In West Virginia, above the Pittsburg seam, 

 over 1,200 feet of Coal Measures rock occur, showing several seams of 



1 Lesley, J. P. : Coal beds in the Subcai boniferons of Pennsylvania. Am. Jour. Sci., 3d ser., vol. 10, 

 1875, pp. 153, 154. 



* A comparison between the Ohio and West Virginia sides of the Alleghany coal field. Proc. Am. 

 Assoc, vol. 24, pt 2, 1875, pp. 84-92. 



