304 CHARLES S. PROSSER 
sandstone on the state line, of the Corry sandstone of Professor 
White in Pennsylvania, of the Berea of northern Ohio.? 
Professor Cushing gave a section of the rocks through 
Warren in which the Berea shale (Sunbury) is given as 55 feet 
in thickness.’ 
It is evident that he included in the Berea shales the blackish 
ones which the writer has referred to the lower part of the 
Cuyahoga formation, for it seems to him that only the 14 feet 
of black shales exposed on the bank of the Mahoning river, 
and included between the top of the Berea grit and the base of 
the overlying g-inch blue sandstone, are to be regarded as the 
equivalent of the Sunbury black shale as exposed at the typical 
localities of Sunbury, and in the bluffs of the Ohio river near 
Buena Vista. 
Dr. Orton stated that “in Trumbull county of northeastern 
Ohio, the Berea [Sunbury] shale grows very thin and thus the 
upper quarry courses come down close upon the Berea grit.’’3 
Later he wrote: 
The Berea shale seems to be reduced in this region [Warren] to a thick- 
ness of about 8 or Io feet. It is, however, well characterized by the Discina 
and Lingula which belong to the horizon. In many places it is almost entirely 
composed of these shells. 
While in describing the Berea grit in the vicinity of Cort- 
land, 7 miles northeast of Warren, Dr. Orton stated: 
Itis always overlain by a thin but very black fossiliferous bed of the 
Berea shale. An excellent section is furnished in the banks and the bed of 
Walnut Creek, within the limits of the village of Cortland, and a half-mile 
below. At the junction of Walnut and Musquito creeks, the flag-rock that 
makes the upper bed of the Berea is found in the bed of the stream. It is 
covered by 8 feet of Berea shale, very black and crowded with its char- 
acteristic fossils.5 
Mr. John F. Carll, who described such a large number of oil 
well sections for the Pennsylvania survey, regarded the Berea 
* Proc, Am. Assoc. Adv. Sci., Vol. XXXVI, 1888, p. 215. 
2 [bid., p. 214, No. 3. 
3 Jbid., Vol. XXX, 1882, pp. 173, 174. 
4 Rept. Geol. Surv. Ohio, Vol. VI, 1888, p. 321. 5 Jbid., p. 331. 
