CEPHALOPODA OF THE CRETACEOUS 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 localities, 
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) TELIFER. 
Plate xu1, 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 toa distinct species; therefore I 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 peculiarity, 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 XVII 7 
