CEPHALOPODA OF THE CEETACEOUS MARLS. 257 



sions and subdivisions are only of specific importance, and that they have 

 mistaken species for subgenera. 



Formation and localities: The species is found in the Lower Marl Beds 

 quite generally throughout the State. It is, however, never common, and 

 is found mostly in detached fragments. It is known from near Burlington, 

 from Mullica Hill, Neversink, Freehold, and many other places in New 

 Jersey; it also occurs in Delaware. Mr. Meek, besides the western locahties, 

 gives in his Check List Mississippi, Alabama, Tennessee, and New Mexico. 

 The species has been often cited from many different localities by various 

 authors. I am, however, very skeptical as to the true identification of 

 many of them. 



Ammonites (Placentaceras) teIjIfer. 



Plate XLi, Figs. 10, 11. 



Ammonites telifer Mort. : Synopsis, p. 38, PL 2, Fig. 7 ; Gabb, Synopsis, p. 17. 



This species was named and figured by Dr. Morton in his Synopsis, 

 from a small fragment of the cast of a chamber, which gives the details of 

 only a part of one lobe of the septum, with small portions of others. No 

 description of the species was given, and no locality mentioned. The frag- 

 ment before alluded to is before me, with two others of much larger size, 

 and are labeled as from New Jersey. The specimens are most probably 

 parts of one individual, and were most likely all in Dr. Morton's hands 

 when he wrote his notice and gave the name. They are evidently frag- 

 ments of a very large specimen having a close resemblance in general form 

 to A. placenta De Kay, but are very different in the details of the septa, and 

 consequently belong to a, distinct species; therefore T think the name worth 

 retaining, although it appears to have been dropped from many lists. The 

 septa of the shell were very closely crowded, as shown on these fragments, 

 for the ramifications of the lobes interlock and interfere one with an- 

 other to such an extent as almost to defy an accurate figure or description. 

 The great peculiaritv, however, and that which seems to separate it from 

 A. placenta, is the very extended and mucronate extremities of the ramifica- 

 tions of both lobes and sinuses; there being so little difference exhibited 



between them as to render it extremely difficult to determine which are 

 MON xviii 17 



