EXPLANATION OF PLATE LIU. 



SPONDYLUS GREGALIS (Morton), p. 486 



1-2. Internal and external views of a large lower valve illustrated 



by Whitfield. 



3. View of an internal cast illustrated by Whitfield. 

 Navesink marl; Crosswicks Creek, f 



DlAXCHORA ECHINATA (Morton) , p. 487 



4-6. Three views of the type specimen, a nearly perfect lower 

 valve. (After Whitfield). 

 Navesink marl. 



