ALLEGHENY FORMATION IN OHIO 125 



row area one has the detailed measurements by Professor Andrews, sup- 

 plemented by Professor Orton's close revision, made ten years later, as 

 well as local contributions by Messrs McMillin, Bownocker, and I. C. 

 White. Throughout most of the area the main strati graphical guides 

 persist, though n some portions the Ames limestone of the Conemaugh 

 becomes shale and the Putnam Hill limestone for the most part can be 

 followed only with uncertainty. The several coal beds are present with 

 more or less regularity, but each of them seems to be absent from con- 

 siderable areas. 



In Vinton county the Upper Freeport is often absent, and when present 

 is so thin that it appears only as a "blossom" in Professor Andrews's sec- 

 tions ; but its place is followed easily by means of its clay and the under- 

 lying limestone, here known as the Shawnee or Buff limestone. The 

 interval to the limestone varies froni 18 feet on the northern edge of the 

 county to 58 feet at 18 miles south, and in this distance the interval from 

 Upper Freeport to Middle Kittanning increases from 90 to 116 feet. 

 The Lower Freeport coal bed does not appear in any of the sections by 

 Andrews and its existence here is uncertain. x\t one time the important 

 coal bed at Hamden furnace was thought to be at this horizon, but closer 

 study proves it to be the Middle Kittanning.. That bed is present 

 throughout, though variable and decreasing in importance southward. 

 It is from 18 to 50 feet above the Lower Kittanning, which is present in 

 most of the sections, though seldom more than 2 feet thick. The least 

 interval is in the northern part of the county, but in the southern town- 

 ships it rarely exceeds 25 feet. The Lower Kittanning is 10 to 20 feet 

 above the Vanport limestone and ore, below which, at 3 to 15 feet, is the 

 Clarion or "Limestone bed," which is persistent, triple, and 2 to 4 feet 

 thick. The Brookville — 25 to 37 feet according to Andrews, 30 to 50 

 feet according to Orton — below the Clarion, is usually present and is 

 workable in four townships, yielding a good coal, though rather high in 

 ash and sulphur. Its thickness is from 2 feet 6 inches to 6 feet 7 

 inches.* 



In Jackson county, south from Vinton, the complete section is shown 

 on the Gallia border, thus: 



Feet. Inches 



1. Upper Freeport 



2. Sandstone 50 



3. Lower Freeport 4 



4. Interval 30 



5. Sandstone 25 



* E. B. Andrews: Vol. i, pp. 93, 107-111, 113, 115, 117-118, 120, 124. 

 E. Orton: Vol. iii, p. 932; vol. v, pp. 999, 1003; vol. vii, p. 280. 



