THE CARBONIFEROUS SYSTEM. 



131 



almost always be satisfactorily correlated. This will be so apparent on 

 an examination of the sheets of grouped sections which accompany this 

 volume, that no further argument will be needed to prove the unity and 

 system which pervades our lower coal series. 



The general arrangement of the strata which form the Lower Coal 

 Measures in Ohio will be seen at a glance by reference to the section 

 given below : 



SECTION OF THE LOWER COAL MEASURES OF OHIO. 



No. 



Strata. 



Feet 



36 

 35 

 34 

 33 

 32 

 31 

 30 

 29 

 28 

 27 

 26 

 25 

 24 

 23 

 22 



21 

 20 



19 

 18 

 17 

 16 



15 

 14 

 13 



12 

 11 

 10 

 9 

 8 

 7 

 6 

 5 

 4 

 3 

 2 

 1 



Red and gray shales of Barren Measures 



Stillwater sandstone, often conglomerate 



Gray shale, alternating with No. 35 



Buff limestone, nodular and ferruginous (''Mountain ore") 



Blackband iron ore, often replacing No. 33 



Coal No. 7, "Cambridge," "Sheridan" and "Groff" coal 



Fire-clay 



Limestone, in eastern and southern counties 



Shale and sandstone 



Coal 6a, "Norris" coal, sometimes a limestone over it 



Fire-clay 



Mahoning sandstone, often conglomerate 



Gray or black shale, alternating with No. 25 



Coal No. 6, " Straitsville," "Bi&v«in" and " Upper Freeport " coal 



Fire-clay 



Limestone, "Freeport," or "White" limestone, in eastern counties 



Gray or black shale, with nodular iron ore at base 



Coal No. 5, "Mineral Point," "Newberry," "Roger," " Lower Freeport' 

 coal 



Fire-clay, often non-plastic and excellent 



Shale and sandstone 



Limestone, " Putnam Hill," or "Gray" 



Coal No. 4, often double, "Flint Ridge cannel," "Strip vein," " Kittan- 



nrng" 



Fire-clay 



Shale and sandstone, sometimes containing Coal 3a 



Limestone, with iron ore, blue, often cherty "Ferriferous" of Pennsyl 



Coal No. 3, Lower limestone coal, " Creek vein " 



Fire-clay, extensively used for pottery 



Shale and sandstone, " Tionesta " sandstone 



Coal No. 2, generally thin, " Strawbridge " coal . 



Fire-clay 



Shale . 



Massillon sandstone 



Gray shale 



Coal No. 1, "Brier Hill," "Massillon, 1 



Fire-clay 



Sandstone and shale....! 



Conglomerate 



'Jackson" coal. 



0-50 



0-50 



0-10 



0-14 



2-7 



3-5 



0-10 



40-50 

 0-6 

 3-5 

 0-50 

 5-50 

 3-12 

 3-5 

 2-8 



25-50 



2-5 



3-6 



20-40 



2-8 



1-7 



2-12 



20-90 



2-6 

 1-4 

 5-15 



30-50 

 1-5 

 1-3 



20-50 



20-80 

 5^0 

 3-6 

 3-5 



10-50 



The following notes on the lower group of coals and some of the strata 

 associated with them will not be without interest and value to those 

 who desire to acquaint themselves with our coal geology : 



