16 AMERICAN JOURNAL 



Observations. — Having worked out of the marl the interior of 

 this beantiful Cretaceous bivalve, I find it differs essentially from 

 the genus Solena of Brown, or Siliquaria, Schumacker, neither 

 of which genera I believe existed before the Miocene period. 



The shell upon which this genus has been founded was dis- 

 covered in North Mississippi, in an ash-colored marl, which also 

 occurs at Eufala, Alabama, and near Haddonfield in New Jersey, 

 in all which remote localities the marl preserves the identical 

 mineralogical and zoological characters, showing that it was once 

 a continuous ocean bed from New Jersey to the Mississippi below 

 Memphis, Tennessee. 



