76 



OHIO FOSSILS 



3. 



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b) 



4. 



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b) 



5. 



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6. 



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7. 



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8. 



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b) 



9. 



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10. 



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11. 



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12. 



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13. 



a) 





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14. 



a) 





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15. 



a) 





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16. 



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b) 



Colonies branching or leaf -like 4 



Colonies hemispherical or honeycomb-like 5 



Intervals between the cups wider than the cups themselves Trachypora 



Intervals between the cups narrower than the cups themselves Coenites 



Tubes polygonal in outline 6 



Tubes round or elliptical in outline 7 



Tubes large (some as much as 3/8 inch in diameter) Hexagonaria 



Tubes all smaller than 3/16 inch Favosites, Emmonsia 



Edges of cups not joined together ,8 



Edges of cups joined together by ring-like expansions Eridophyllum 



Tubes free except where one branches off from another Cylindrophyllum 



Tubes free, joined by distinct crossbars 9 



Diameter of tubes less than l/8 inch Syringopora 



Diameter of tubes more than l/8 inch Synaptophyllum 



Coral button-shaped Hadrophyllum 



Coral horn or tube -shaped ,11 



Cup horn -shaped 12 



Cup tube -shaped, much longer than wide Siphonophrentis gigantea 



Septa prominent, numerous 13 



Septa not prominent, cup with numerous blister- 

 like growths Cystiphyllum 



Septa with wavy edges 14 



Septa with straight edges 15 



Septa slightly twisted at center Heliophyllum 



Septa straight to center Zaphrentis 



Only half of the septa reach to the center of the cup Siphonophrentis 



Most of the septa reach to the center of the cup 16 



Septa less than 90 in number. Heterophrentis 



Septa more than 90 in number Aulacophyllum, Cyathophyllum 



The following common genera are arranged in the same order as the key. The first twelve 

 are colonial forms and the last eight are solitary or horn corals. Siphonophrentis gigantea ap- 

 pears twice in the key because the full-grown specimens are very different from young ones and 

 from other species of the genus. 



of Aulopora , Ceratopora , and Romingeria are very similar. They are colonial but 

 do not grow in colonies of parallel tubes. Instead, the tubes branch out from 

 each other in a network of cells (see fig. 151). A. expatiata (fig. 151) is found 

 in the Columbus limestone and three other species in the Delaware. 



The next two genera have stick-like, branching colonies. In Trachypora 

 the cups are fewer and farther apart than in Coenites. The cups are separated 

 by an interval wider than the cups themselves in Trachypora (fig. 152) and 

 narrower than the cups in Coenites. Trachypora elegantula is found in the 

 Tenmile Creek dolomite. 



