GEOLOGICAL SECTION OF NEW JERSEY BL 
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Tinton inclusive constitute a larger faunal unit, much more sharply 
separated from the faunas above and below than are any of its con- 
stituent faunules from each other. Weller has shown that this larger 
faunal unit is made up of two or more distinct facies, one of which, 
the Cucullaea fauna, is characteristic of the more glauconitic beds; 
namely, the Merchantville, Marshalltown, Navesink, and Tinton, 
while the other facies characterized by Lucina cretacea or its associates 
occurs in the clays or clayey sands of the Cliffwood, Woodbury, 
Wenonah, and Red Bank formations. ‘The two facies existed con- 
temporaneously and migrated backward and forward across the 
present outcrop of these beds in New Jersey as deeper or shallower 
water conditions prevailed. The larger faunal unit is closely related 
to the Ripley fauna of Alabama, Mississippi, and Texas. On 
faunal evidence all the formations from the Magothy to Tinton in- 
clusive are referable to the Senonian of Europe, although on floral 
evidence the Magothy might be regarded as Cenomanian. 
Hornerstown marl.—The Hornerstown marl is a bed of glauconite 
with clay and sand and not differing materially from the Navesink. 
Its fauna is meager but is totally different in its essential characteristics 
from the faunas of all the underlying formations. Terebratula 
harlami, Cucullaea vulgaris, and Gryphaea dissimilaris (Weller) are 
characteristic forms. A shell bed at the top of the formation is a 
conspicuous feature at many localities. ‘The thickness is 30 feet or 
less. At the north it rests with apparent conformity on the Tinton, 
where that is absent it lies on the Red Bank, and farther south it is con- 
tinuous with the Navesink, owing to the disappearance of the Red 
Bank. It is conformably overlain by the Vincentown except where 
overlapped by Miocene formations. It is the Middle Marl of Cook, 
the Sewell marl of Clark, and is a part of the Rancocas group. 
Vincentown sand.—The Vincentown sand presents two phases, 
a calcareous or limesand, semi-indurated, and largely a mass of broken 
bryozoan, echinoid, coral, and other calcareous remains, and a glau- 
conitic quartz-sand phase. The two phases occur in alternating 
layers, although the former is more common in the basal portion, 
particularly to the south, while the quartz-sand phase predominates 
in Monmouth County. The fauna of the limesand phase contains 
large numbers of bryozoa, echinoids, and foraminifera, while in the 
