482 The Ohio Naturalist. [Vol. IX, No. 6, 



THE CONEMAUGH FORMATION IN SOUTHERN OHIO.^ 



D. Dale Condit. 



Introduction. 



During the summer of 1907, the writer was engaged by the 

 Geological Survey of Ohio in tracing and mapping the Pittsburg 

 and Pomeroy coals in southern Ohio. The seams were traced 

 from the Ohio River in Lawrence County northeastward across 

 Gallia, Meigs, Athens and into Morgan County. This field work 

 gave the writer an extensive acquaintance with the Conemaugh 

 as far down the section as the Cambridge limestone and is the 

 basis of this paper. 



Nomenclature of the Formation. 



The term Conemaugh was first applied by Franklin Piatt, ^ in 

 1875, to his so-called "Middle Barren Measures" and "Mahoning 

 sandstone." Later the name was used in Maryland^ to designate 

 all the rocks between the base of the Pittsburg coal and the top of 

 the Upper Freeport coal. With these limits, the name is today 

 in general use throughout the Appalachian Basin. In 1901, 

 Charles S. Prosser* adopted for Ohio the formation names 

 Allegheny, Conemaugh, Monongahela and Dunkard of the 

 Maryland Survey in place of Lower Productive, Lower Barren, 

 Upper Productive and Upper Barren Coal Measures as adopted 

 by Dr. Orton from Rogers' classification in Pennsylvania. 



Generally, the Allegheny, Conemaugh, Monongahela and 

 Dunkard are ranked as formations, but Dr. I. C. White, in his 

 reports on the Coal Measures of West Virginia'', prefers to 

 consider these as series. 



General Description. 



The thickness of the Conemaugh in .southern Ohio is usually 

 325 to 375 feet which is little more than half the thickness found 

 along the northern outcrop in Pennsylvania." A shaft at 

 Canaanville, Athens County, shows the interval between the 

 Pittsburg and Middle Kittanning coals to be 43G feet.'^ Although 

 the base of the Conemavigh can not be conclusively located in this 

 shaft section, it is probable that the formation is here less than 

 375 feet thick. The following general section shows the prin- 



1. Published by pwinissiou of J. \. Bowriocker, State Geologist. 



2. Sec. Geol. Surv. Pa., H. p. 8. 



3. O'Harra: Maryland Geol. Surv. Allegany County, 1900, p. 86-118, and Prosscr: 



Jour., Geology, Vol. IX, 1901, p. 426. 



4. Am. Jour. Sci. 4th Ser. Vol. XI, March, 1901, p. 199. 



5. AVest Virgiuia Geol. Surv. 1908, Vol. Ila, p. 622, and Geol. Surv. Ohio, 4th Sen, 



Bull. 7, 1). 11. 



6. J. J. Stevenson, Carboniferous of the Appalachian Basin, \^. ;i46. 



7. Geol. Surv. Ohio, 4th Ser., Bull. 9, p. 212. Depth of shaft should read 442 ft. instead 



of 412 ft. 



