Biostratigraphic Analysis of Columbus Limestone

Period	Formation	Member	Stauffer Zone	Biostratigraphic Zone
Mississippian	Bedford Shale
Disconformity
Upper Devonian	Ohio shaleDark shale700 ft			Fossils very scarce
Middle Devonian	Olentangy Shale Light shale 30 feet			Fossils very scarce, found mostly in nodular limestone
	Delaware Formation Impure limestone 36 feet		M	5th bone bed on top 4th bone bed near bottom
			L	3rd bone bed Hadrophyllum dorbignyi Zone
			K	Grammysia biscucota Zone
			J	Tentaculites scalariformis Zone also crinoid lens
			I	Martinopsis maia Zone
	Columbus Limestone Normal limestone 105 feet	Delhi Member (Klondike)	H	2nd bone bed on top Nucleocrinus verneulli Zone 1st bone bed near bottom
			G	Goldringia cyclops Zone (Cephalopod zone)
			F	Brevispirifer gregorlus Zone
			E	Spirifer macrothyris Zone
		Eversole Member	D	Laevidentalhum martinei Zone (Gastropod zone)
		Bellpoint Member	C	Coral Zone
			B	Fossil scarce, poorly preserved
			A	Conglomerate
Disconformity
Silurian	Monroe Formation