NATURAL SCIENCES OP PHILADELPHIA. 93 



proportionally decidedly smaller. This, I suspect, belongs to a 

 distinct species; but, as the specimen is too much eroded to show 

 its surface character clearl3', I have preferred to refer it doubt- 

 fully, for the present, to the same. 



Locality and position. Marblehead, Ohio. Corniferous group 

 of the Devonian. 



isn.] 



