26 J. J. STEVENSON — LOWER CARBONIFEROUS, APPALACHIAN BASIN 



to the Upper Chemung conglomerate or first Venango oil-sand; while 

 in Brady township of Butler, about 25 miles southwest from Edenburg, 

 sandstone is 90 feet, divided midway b}^ 10 feet of shale; at Pittsburg, 

 about 30 miles south from the last, the sandstone is 170 feet, with 10 feet 

 of shale at 20 feet from the bottom. Here one is 45 miles due west from 

 the Conemaugh gap through Chestnut ridge, where the upper plate of 

 the Pocono is a sandstone 250 feet thick. At Murraysville, Westmore- 

 land count3^, 15 miles east from Pittsburg, the sandstone is 200 feet thick 

 resting on shales. The record in Mount Pleasant township of Washing- 

 ton county shows 106 feet of white sandstone, separated b}^ 22 feet of 

 shale from 11 feet of fine white sand, below which are shale and sand 

 for 112 feet, a total of 251 feet; at Washington, in the center of the 

 same county, the record is incomplete; it gives sandstone 120 and 30 

 feet, separated by 2 feet of shale ; but at Waynesburg, in Greene county, 

 the record shows 230 feet of white sandstone underlying the Mauch 

 Chunk.* It is quite possible that the sandstone in the borings may 

 represent the Shenango and the Sharpsville, and that the intervening 

 shale, so irregular, ma^^ be the Meadville. Where thin it may have 

 been neglected by the driller. The records in West Virginia bear out this 

 suggestion. 



Along the northern and ivestern outcrop in Ohio. — The Shenango sandstone 

 has been followed by Doctor White into Trumbull count}^ of Ohio, where 

 it is about 15 feet thick and rests on 80 feet of Meadville shales. Pro- 

 fessor Orton regards the Logan sandstone of Ohio as the Shenango sand- 

 stone, but includes also in the equivalence the overlying Shenango 

 shales of White, which, as will appear in the second chapter, must be 

 considered with the Mauch Chunk. 



The Logan, in Ohio, is double, sandstone above and conglomerate 

 below, at the typical localities. Followed into Ohio from Pennsylvania, 

 the rock becomes finer, the sandstone becoming shale and the conglomer- 

 ate, sandstone. In the counties of Knox, Holmes, Richland, and Cochoc- 

 ton, the sandstone is represented by the Olive shales of M. C. Read, which 

 are upward of 200 feet thick, but farther south the mass becomes a fawn- 

 colored, even-bedded, fine grained sandstone. The conglomerate gains 

 in coarseness westward and southward, being a coarse rock in Wayne, 

 Holmes, Cochocton, Knox, Licking, Fairfield, Hocking, Vinton, and Ross 

 counties, which, as Professor Orton observes, mark '' the northwestern arc 

 of the sea boundary in Sub-Carboniferous time." The conglomerate is 

 not always continuous, there being usually, as Professor C. L. Herrick 

 has shown, two beds of conglomerate separated by layers of fine sand- 



* J. F. Caill : Ann. Rep. second Geol. Surv. Penn. for 188fi. These notes have been taken from 

 the plates in Mr CarlPs discussion, formiua; part ii of this annual report. 



