In the Mesozoic

Mesozoic

The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 Era, Appalachia was a land area which is now an eastern part of the USA and Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, separated from Laramidia

Laramidia

Laramidia is a name coined by J. David Archibald in 1996 to describe an island continent that existed during the Late Cretaceous period, when the Western Interior Seaway split the continent of North America in two. Two landmasses existed: the eastern one is called Appalachia; Laramidia is the name...

 by the Western Interior Seaway

Western Interior Seaway

The Western Interior Seaway, also called the Cretaceous Seaway, the Niobraran Sea, and the North American Inland Sea, was a huge inland sea that split the continent of North America into two halves, Laramidia and Appalachia, during most of the mid- and late-Cretaceous Period...

, which shrank, divided across the Dakotas, retreated south towards the Gulf of Mexico and finally dried up.

Fauna

From the Turonian

Turonian

The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...

 age of the Late Cretaceous to the very beginning of the Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

, Appalachia was separated from the rest of North America. Because of this, its fauna was isolated, and developed very differently from the tyrannosaur and ceratopsian dominated fauna of the western part of North America, the geologist's "Laramidia

Laramidia

Laramidia is a name coined by J. David Archibald in 1996 to describe an island continent that existed during the Late Cretaceous period, when the Western Interior Seaway split the continent of North America in two. Two landmasses existed: the eastern one is called Appalachia; Laramidia is the name...

". Due to few fossiliferous deposits and many of Appalachia's fossil formations being destroyed by the Pleistocene ice age, little is known about Appalachia. In addition, due to lack of interest in Appalachia, many fossils that have been found in Appalachia lie unstudied and remain in the inaccurate genera to which they were assigned in the days of E.D. Cope

Edward Drinker Cope

Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...

 and O.C. Marsh. However, a few fossil sites, such as Ellisdale in New Jersey

Ellisdale Fossil Site

The Ellisdale Fossil Site is located in the valley of the Crosswicks Creek in Monmouth County, New Jersey. The site has produced the largest and most diverse fauna of Late Cretaceous terrestrial animals from eastern North America, including the type specimens of the teiid lizard Prototeius stageri...

, have given us a glimpse into this forgotten world of paleontology.

In Cretaceous North America, the dominant predators were the tyrannosaurs, huge predatory theropods with proportionately massive heads built for ripping flesh from their prey. Tyrannosaurs were the dominant predators in Appalachia too, but rather than the massive tyrannosaurine tyrannosaurs, the dryptosaur

Dryptosaurus

Dryptosaurus was a genus of primitive tyrannosaur that lived in Eastern North America during the middle Maastrichtian stage of the Late Cretaceous period. Although largely unknown now outside of academic circles, a famous painting of the genus by Charles R...

s were the top predators of Appalachia. Rather than developing the huge heads and massive bodies of their kin, dryptosaurs had more in common with the basal tyrannosaurs like Dilong

Dilong (dinosaur)

Dilong is a genus of small tyrannosauroid dinosaur. The only species is Dilong paradoxus. It is from the Lower Cretaceous Yixian Formation near Lujiatun, Beipiao, in the western Liaoning province of China. It lived about 130 million years ago...

and Eotyrannus

Eotyrannus

Eotyrannus was a genus of tyrannosauroid theropod dinosaur hailing from the Early Cretaceous Wessex Formation beds, included in Wealden Group, located in the southwest coast of the Isle of Wight, United Kingdom...

, having long arms with three fingers, a more lithe skull and body, and were not as large as the largest tyrannosaurids. Two genera of Appalachian dryptosaurs are known, Dryptosaurus

Dryptosaurus

Dryptosaurus was a genus of primitive tyrannosaur that lived in Eastern North America during the middle Maastrichtian stage of the Late Cretaceous period. Although largely unknown now outside of academic circles, a famous painting of the genus by Charles R...

and Appalachiosaurus

Appalachiosaurus

Appalachiosaurus is a genus of tyrannosauroid theropod dinosaur from the Late Cretaceous Period of eastern North America. Like almost all theropods, it was a bipedal predator. Only a juvenile skeleton has been found, representing an animal over 7 meters long and weighing over...

. Though Ornithomimid bones have been reported from Appalachia, it is now believed that these are the bones of juvenile dryptosaurs.

Another common group of Appalachian dinosaurs were the hadrosaurs. While there was a staggering diversity of hadrosaurs on the western side of the seaway, the hadrosaurs of Appalachia were more primitive in nature and less diverse, though this perception is probably due to the lack of fossil sites in eastern North America. Many hadrosaurs are known from Appalachia, however, such as Lophorhothon

Lophorhothon

Lophorhothon is a genus of hadrosauroid dinosaur from the Late Cretaceous, the first genus of dinosaur discovered in Alabama.-Discovery and naming:...

, Hypsibema

Hypsibema

Hypsibema is a little-known genus of dinosaur from the Late Cretaceous . Its giant fossils were found in the U.S. states of North Carolina and Missouri...

, and Hadrosaurus

Hadrosaurus

Hadrosaurus is a valid genus of hadrosaurid dinosaur. In 1858, a skeleton of a dinosaur from this genus was the first dinosaur skeleton known from more than isolated teeth to be found in North America. In 1868, it became the first ever mounted dinosaur skeleton...

. The hadrosaur Claosaurus

Claosaurus

Claosaurus is a genus of primitive hadrosaurid that lived during the Late Cretaceous Period .Evidence of its existence was first found near the Smoky Hill River in Kansas, USA in the form of partial skull fragments and as an articulated postcranial skeleton...

, known from a specimen which floated into the Interior Seaway and was found in Kansas, might also be from Appalachia, since it was found closer to the Appalachia side of the seaway and is unknown from Western North America. Hypsibema, over fifty feet long, was the titan amongst these,and must have certainly taken the place of sauropods in Appalachia.

The nodosaurs, a group of large, herbivorous armored dinosaur

Ankylosauria

Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are first known to have appeared in the early Jurassic Period of...

s resembling an armadillo

Armadillo

Armadillos are New World placental mammals, known for having a leathery armor shell. Dasypodidae is the only surviving family in the order Cingulata, part of the superorder Xenarthra along with the anteaters and sloths. The word armadillo is Spanish for "little armored one"...

, are another testament to Appalachia's difference from Western North America. By the latest Cretaceous, nodosaurs were scarce in Western North America, existing only in specialized forms like Edmontonia

Edmontonia

Edmontonia was an armoured dinosaur, a part of the nodosaur family from the Late Cretaceous Period. It is named after the Edmonton Formation , the unit of rock it was found in.-Description:...

and Panoplosaurus

Panoplosaurus

Panoplosaurus is a genus of nodosaurid dinosaur. It was one of the last known nodosaurids, living during the Late Cretaceous in what is now North America; fossils have been located in Alberta, Canada....

. Nodosaur scutes have been found in Eastern North America, not diagnostic enough to identify the species, but enough to tell that these armored dinosaurs were reasonably common in Appalachia.