912 GEOLOGY OF OHIO. 



tainly one of the lowest coal seams of Southern Ohio. It has not been 

 established that the various exposures of low coal found on the western 

 side of Jackson and Vinton counties, and on the eastern side of Pike, all 

 belong to the same horizon, but it seems probable that they are to be so 

 referred. The westernmost of these expoaures are all tntrorConglomeraU 

 coals. They rest directly, or with the interposition of a few feet of shale 

 and fir»-clay, upon conglomerate rock, and they are covered with heavy 

 ledges of conglomerate. On sections 21, 22, 27, 28, of Jackson township, 

 Jackson county, not less than forty feet of pebble rock are shown above 

 the coal. On the east side of section 26, same township, on the land of 

 J. Wilson Case, a seam, measuring three feet in thickness, is overlain by 

 a ledge of very coarse conglomerate, the pebbles of which are cemented 

 with iron ore. The overlying conglomerate is also shown in full force on 

 sections 19, 22, and 31 of Jackson township. Pike county, and also in 

 Union and Marion townships of the same county. 



The underlying conglomerate in all these cases is the first main seam 

 that is reached in the ascending scale of the State. The Pike county 

 sections furnish the means of connecting the coal seams directly with 

 well-known and definitely-marked horizons of the lower rocks. The 

 coal is not more than five hundred and seventy feet above the Huron 

 Shale, and not more than four hundred and fifty feet above the Waverly 

 Black Shale. 



2. About one hundred feet above the Shaft Coal a second seam occurs, 

 which, like the one already named, is locally of great economical im- 

 portance. It is known as the Petrea Coal, the Wellston Coal, and the 

 Hill Coal of Jackson coanty. 



No discussion of the«e lower seams i» in place here, and^no correlation 

 of them with the lower coals of other sections of the State has been at- 

 tempted. Numbers have not been RSfigned to them in the engraved 

 chart of the Coal Measures, but their Sub-carboniferous age is there 

 asserted in the place that is given them, viz , below the Maxville Lime- 

 stone. 



The position of two other seams above the Wellston Coal, but below th« 

 Zoar Limestone, is also indicated in the chart, but no mention of them 

 will be made here. 



3. We come now to a horizon that is everywhere conspicuous for the 

 presence of the cha'-acteristic elements of the Coal Measure rocks, viz., 

 fire-clay, vi al, limestone, and iioa ore. It is the horizon of the Blue or 

 Zoar Ijirii 4one, and of the Main Block ores. The coal seams associated 

 with ihu limestone can be traced with perfect distinctness through all of 

 the marginal counties of the coal field from Pennsylvania to the Ohio 



