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Judithian of eastern U.S.
A recent request in Dinosaur Digest for "information on Judithian ages
faunas of eastern North America" has prompted the following brief
overview. Dinosaur-bearing Judithian-aged strata (mid to late
Campanian) along the Atlantic Coast include the Marshalltown Formation
of Delaware and New Jersey; the Woodbury Fm of New Jersey; the Black
Creek Fm of North Carolina; and the Donoho Creek Fm of South Carolina.
Judithian dinosaurs of the Gulf Coast and Mississippi Embayment have
come from the Demopolis Chalk of eastern Alabama, the upper Blufftown
Fm of Georgia (may be early Campanian), and the unnamed unit from the
Chronister site of southeast Missouri (the age of the latter is not
well constrained). If anybody knows of additional units, please let
Basically, all of these units have produced meager and incomplete
dinosaur material, and I'm not sure a direct comparison with the
unbelievably diverse and well-preserved Judithian faunas of western
North America is a completely fair one. As far as I'm concerned, the
absence of hypsilophodonts, ceratopsians, pachycephalosaurs, and
ankylosaurs in the east is so much negative evidence, not definitive
proof of there actual absence. Here's what's actually known from the
-indet. theropod (Demopolis Chalk, cited in Schwimmer et al., 1993 as
a possible tyrannosaurid)
-indet. theropod material (some of these have been referred to
"Dryptosaurus", Carpenter et al. 1997, indicate that these "are based
on fragmentary material and only superficially resemble Dryptosaurus;
they should be considered nomina dubia)
-?Albertasaurus sp. (Blufftown, Schwimmer et al., 1993)
-indet. ornithomimid spp.
-indet. hadrosaurid spp.
-Hadrosaurus foulkii (a larger hadrosaurid previously named
Ornithotarsus has been provisionally included with H. foulkii, but it
could be a separate taxon).
-"Hypsibema crassicaudata" (inclusion in hadrosaurinae is provisional;
status doubtful, may be synonym of Hadrosaurus).
-"Hypsibema missouriensis" (hadrosaurid material from Missouri,
possibly of Judithian age; a nomena dubia, possibly synonym of
This relatively meager material provides little basis for comparison
I'd say. However, occurrences of mammal teeth in the Marshalltown Fm
of Ellisdale, NJ, strongly indicates that faunal exchange of Campanian
vertebrates did indeed occur between eastern and western North
America. These include "cf. Cimolomys clarki" and Protalphadon lulli
(see Grandstaff et al.,1992, JVP, v. 12, p. 218), which are common
mammals in the Judith River Formation of Montana and Alberta.
Possible tyrannosaurids from the east futher underscore the
possibility of episodic faunal exchange.