The Primitive Fishes 



269 



f Cleveland shale Fish fossils abundant. (F)* 



" O'hio I Erie shale " " absent. (M) 



] Huron shale " " present. (F) 



Shale Hamilton shale " " absent. (M) 



[ Corniferous limestone " " abundant." (F) 



To the above might here be added Claypole's "Section of 

 Cleveland Shale in Cuyahoga County," (Fig. 43) with the 

 leading fish types indicated from each zone {8y: 316) : 





Large Cladodus 

 Dinichthys terrelli 

 Gorgonichthys 



Titanichthys 



Titanichthys clarki 

 T. rectus 



Small Cladodus 



Dinichthys intermedius 

 Titanichthys 



Dinichthys intermedius 



Coccosteus 



No fossils at Brooklyn 

 Fossils on Rocky River 



No fossils 



Fig. 43. Section of Cleveland Shale, showing relative positions 

 of the beds containing abundant and large types of Arthrodira. 



From the Delaware or Sandusky series of the Cornifer- 

 ous limestone Newberry described Machaeracanthus sul- 

 catiis, M. major and M. peracuttis, also a species of Clad- 

 odus, Ptychodus and Rhynchodus. Such furnish ample 

 proof that primitive elasmobranchs and chimaeroids had 



•The present writer has appended in brackets the letters (F) for freshwater and 

 (M) for marine deposits. 



