66 General Notes. [Jan, 
the main trunk line is replaced by irregular branches beginning 
with species which we have styled tertiary radicals. ese have 
either the depressed or compressed form of whorl, are discoidal, 
and, therefore, resemble the primary and secondary radical 
throughout life. But, on the other hand, they are often highly 
ornamented with spines and ribs, and have more complicated 
sutures, ‘ 
_ The tertiary radicals give rise to series of species, which may 
become excessively involute and otherwise modified in the 
to continue the direct lines of descent from the Trias, so far as 
progressive forms are concerned. 
But when we turn our attention to retrogressive forms, the 
story is different. Series of degraded or distorted forms occur 
in the Jura and Cretaceous, and several families afford good ex- 
amples. In these series we can usually trace an origin in some 
close-coiled, discoidal, ornamented shell, which belongs to the 
tertiary radicals, or is not far removed from them in its aspect. 
We have frequently pointed out the nature of these degrada- 
tions. They are similar to the senile degenerations observed in 
the individuals of the tertiary radicals and other species of the 
progressive series of the Ammonoids. These geratologous 
transformations, whether occurring in the senile degenerations of 
a shell or in a series of species, tend to produce similar results, 
namely, the decrease in size and uncoiling of the whorl, destruc- 
tion of ribs and spines, reduction of sutures to more primitive 
proportions, The final result, as we have often said, is a straight 
almost smooth ‘shell, Baculites. We now wish to assert that 
Baculites is a polyphyletic group derived from many tertiary 
radicals, and separable into a considerable number of distinct 
genetic groups.—A/pheus Hyatt. é 
New Jersey Cretaceous.—The different beds of the New 
Jersey Cretaceous consist of layers of sedimentation, almost 
always conformable, which have been distinguished by the State 
Geological Survey as Plastic Clays, Camden Clays, Lower Marls, 
Middle Marls, Upper Marls, with which series in this paper the 
Eocene Marls have been united. Beds of sand separate these 
beds, and the fossils are limited to the green marls and clays. 
The clay-beds in their lower part have yielded five species of 
fossils, shells which are entirely estuarine in character, the genera 
recognized being Astarte, Corbicula, Gnathodon, and a new 
SS Dania This last genus resembles the Jurassic 
u 
_ At the upper limit of the clay-beds in the clay marls are found 
= ironstone nodules containing casts of fossils identical with 
ee Won me ee ee the Clay Marie aE Crols 
i 
