184 
GEOLOGY: CLARK, BERRY AND GARDNER 
Matawan. — The earliest fauna of any extent occurs in the Matawan 
from which 175 to 185 species have been described in New Jersey and 
Maryland. Five faunal zones have been differentiated in north-central 
New Jersey, where the Matawan is best developed, but it has not been 
possible to carry any but the lowest of these south of the Delaware- 
Maryland line. The Merchantville, together with the Woodbury which 
merges into it in southern New Jersey, has been recognized along the 
Chesapeake and Delaware Canal just east of the state line. Although this 
fauna is a small one of only about 50 species, it contains the elements of 
one of the most widely distributed and best characterized biotas of the 
entire Upper Cretaceous, a fauna represented in the Mortoniceras subzone 
of the South Atlantic and Gulf states, the Austin Chalk of Texas, the 
Niobrara of the Western Interior, and the Emscher beds of north-central 
Europe. 
The late Matawan deposits were probably laid down in more shallow 
waters. Their contained faunas are consequently more restricted in 
their distribution and less cosmopolitan in their affinities. The Mar- 
shalltown of New Jersey which is best characterized by the abxmdance 
of the ponderous Ostreids, such as Exogyra and Gryphaea, is quite pos- 
sibly represented in the Matawan oyster banks along the Chesapeake 
and Delaware Canal west of St. Georges. These beds are doubtless the 
time equivalent of at least a part of the Exogyra ponderosa zone of the 
South Atlantic and Gulf states, a faunal zone which has been recognized 
in the upper Black Creek of North and South Carolina, the lower Ripley 
of Georgia and eastern Alabama, the lower Selma of central and west- 
em Alabama, Mississippi, and Tennessee, and the upper Eutaw of Mis- 
sissippi and Tennessee. 
Monmouth. — The Monmouth formation has furnished the most pro- 
lific and diversified fauna of any of the Upper Cretaceous, over 250 
species having been determined and of these about 75% are peculiar. 
Three faunal zones have been differentiated in New Jersey but it is 
impossible to trace the New Jersey horizons southward into Maryland 
with any assurance. The fauna of the Sassafras River area, although 
very prolific, is very poorly preserved and the determinable species are 
none of them diagnostic of a particular facies. However, the abundance 
of Belemnitella americana, in the Eastern Shore deposits of Delaware and 
Maryland suggests the Navesink, while Sphenodiscus is peculiarly char- 
acteristic both of the Tintonof New Jersey and the prolific Prince George's 
County fauna in Maryland. It is exceedingly improbable, however, 
that there is any appreciable time interval involved in these faunal 
differences. 
