GEOLOGY: CLARK, BERRY AND GARDNER 
185 
The general aspect of the Monmouth biota is more southern than 
that of the Matawan and it is probable that the slight depression of the 
seas which initiated the Monmouth broke down the barriers which had 
earlier prevented free communication with the inshore life of the south 
Atlantic. 
The Monmouth is at least the partial time equivalent of the Exogyra 
costata zone which has been recognized in the Peedee sand of North 
and South Carolina and in the Ripley and Selma chalk of the Gulf 
states. A number of identical species occur in the Fox Hills of the West- 
ern Interior while the ensemble is very similar to that of the Upper Cam- 
panian of the Belgian border and the so-called Maestricht beds. 
Rancocas. — Two horizons have been recognized in the Rancocas of 
New Jersey, the Hornerstown glauconitic marl and the Vincentown 
yellow sand" but these divisions are absent south of the Delaware 
Bay. The diagnostic features of the fauna developed in Delaware are 
essentially those of the Vincentown — a prolific bryozoan fauna with 
Terehratula harlani in abundance and a very meager moUuscan repre- 
sentation. Only about 15 species have been determined, all of them 
bivalve, over half of which are restricted to the Rancocas. Five have 
been found at older horizons, while Ostrea vomer and Terehratula harlani 
have been reported as surviving the break between the Mesozoic and 
Cenozoic although there is doubt in both cases as to the identity of the 
species. 
The mollusca of Delaware are curiously dissimilar from those of New 
Jersey, none of the few characteristic species of New Jersey occurring in 
Delaware, while the abundant Delaware Gryphaea to which the charac- 
teristic Vincentown bryozoa attach themselves, is apparently not present 
in New Jersey. 
There is no closely allied fauna in this country and its closest ana- 
logue is apparently in northern Europe. Although there is little direct 
evidence for its correlation with the Danian yet the general facies of the 
two faunas is very similar. Both are characterized by an extensive 
bryozoan fauna and the absence of Belemnitella. At the same time the 
fau^a is not Tertiary in aspect and it seems improbable that it can be- 
long to that horizon. 
Manasquan. — The Manasquan is closely related to the Rancocas 
both faunally and stratigraphically. Its fauna is not characteristically 
Cretaceous although the general assemblage of forms suggests its asso- 
ciation with that division rather than with the Tertiary. It is regarded 
as Danian. It has no equivalents as far as known among American 
formations elsewhere. 
