THE SUNBURY SHALE (OF (OfHLO 291 
feet 4 inches of fire clay and blue and drab shale, as given on 
Andrew’s section. His section gives a thickness of 20 feet 9 
inches from top of sandstone (Berea) to the base of the ‘ City 
ledge’ (Buena Vista stone), and my section for the same por- 
tion of the Waverly is 21 feet, or 3 inches greater, which is a 
very close agreement when it is remembered that the location 
Fic. 3.—The two layers of Buena Vista sandstone and overlying shales on Lower 
Twin Creek, northwest of Buena Vista. 
of the two sections is two miles or farther apart. Succeeding 
the zone of fire clay and shale is the Buena Vista stone or ‘City 
ledge,” in two layers separated by a shale parting of 2% inches, 
with a total thickness of 5 feet 7% inches. 
Professor Locke gave the thickness of the ‘City ledge” at 
Rockville as 2% feet, and stated that it had ‘‘a stratum of shale 
about 15 feet below it,” the context showing that he evidently 
meant the shale had a ¢hickness of about 15 feet, ‘‘and another 
of about the same thickness above it.”’* 
t Second Ann. Rept. Geol. Surv. Ohio, p. 264. 
