108 



The Middle Devonian Deposits of Maryland 



Geological Range of Middle Devonian Species in Maryland and New Yokk. — Continued. 





SPECIES 



Maryland 



New York 





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Middle 

 Devonian 

 lioniney 



Upper Devonian 

 Jennings 



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5= 

 O 



Middle 

 Devonian 



Upper 

 Devonian 





B 



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c 



Portage 



tic 



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B 



144 

 145 

 146 

 147 



MOLLUSCA— GASTROPODA.— Continued. 



Cjcloncma hamiltoni;E Hall (?) 



Cyclonema liratiim var. grabaui Prosser 



Cyclonema ( ?) marylandense Prosser 



Naticopsis sp 





• 

 » 





* 



* 



* 







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* 



"t 







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 • 



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t 



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\\ 





» 

 « 



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::\ 



148 

 149 



Macrochilus hamiltoniae Hall 





150 



151 

 152 

 153 

 154 



Platyceras erectum Hall (?) 



Platyceras cf. symmetricuin Hall 



Diaphorostoma lineatum (Conrad) 



Platyostoma cf. eiiomphaloides Conrad 



Stvliolina tissurella (Hall) 





155 

 156 

 157 



158 



Tentaculites attenuatus Hall 



Tentaciilites belliilus Hall 



Tentaculites bellulus var. potomacensis Prosser 





159 







160 



161 

 162 

 163 

 164 

 165 

 166 

 167 

 168 

 169 

 170 

 171 

 172 



Coleolus tenuicinctiis Hall 



MOLLUSCA— CEPHALOPOD.\. 



Orthoceras bebry.\- Hall (?) 



Orthoceras subulatum Hall (?) 



Orthoceras constrictum Vanuxem 



Orthoceras cf. exile Hall 



Orthoceras telamon Hall (?) 



Orthoceras cmaceratum Hall (?) 



Orthoceras cf. aulax Hal! 



Spyroceras crotalum (Hall) 



Spyroceras nuntium Hall 



Spyrnceras clarkei Prosser 



cf. Gomphoceras pingiie Hall 





173 



Bactrites aciculus Hall 





174 

 175 



;7fi 



Agoniatites expansus (Vanuxem) 



Parodiceras discoideum (Conrad) 



ARTHROPODA. 

 Cvpha.spis cf. stcphanonhora Hall 



•• 



177 

 178 

 179 



H<.malonotus dekayi (Green) 



Phacops rana (Green) 





180 







181 

 182 

 183 

 184 



Dalmanites (Cryphsus) boothi (Green) 



Dalmanites marylandicus Prosser 



Leperdil ia ? cf. subrotuniia Ulricli 



Rolliii i.jifi^ula J tnes 





185 



Rdllia ohcsa Uliich 







•■ 



T = related form. 



