EARTH WHEN PLANT FOSSILS
of WEST VIRGINIA LIVED

During this period West Virginia was a tropical coastal swamp covered by forests of primitive trees which lived, died, and accumulated to form thick peat beds. Transformed by subsequent heat and pressure these beds became the great bituminous coal deposits of North America and Europe, which are used to manufacture steel and to produce electricity.

Floating atop a mantle of hot, ductile rock, the continents and ocean plates drift like gargantuan icebergs, crashing into each other, building mountain ranges and volcanic belts as they go.

The phenomenon is known as continental drift and the process has been going on for hundreds of millions of years-- at rates measured in only a few centimeters per year.

Two types of rocks comprise Earth's outer crust:

• 1)_oceanic crust (heavy, basaltic rock) and
• 2)_continental crust (light, granitic rock).

Oceanic crust is being continuously created through the process of seafloor spreading, and continuously consumed through subduction. Because of this continuous recycling, no oceanic crust is older than 190 million years. See an animation of subduction in action.

Continental crust is generally not recycled through subduction. Consequently the rocks in the middle of continents can be more than 2.5 billion years old. The age of the rocks generally decrease toward the continental margins, representing lands added to the original continental core throughout geologic time by processes like convergence and continental acretion. See an animation of convergence in action.

325 million years ago during the Carboniferous Period , North America and Europe were converging to form the supercontinent Euramerica. 

Part of Eastern Europe and most of northeast Asia were joined to form the ancient continent Angra at this time.

Africa, Australia, India, and Antarctica together comprised the supercontinent of Gondwanaland.

EARTH WHEN DINOSAURS LIVED

The first dinosaurs evolved during the Triassic Period as all the continents converged to form a single giant supercontinent called Pangea.

The Jurassic Period followed (213 million years ago) marked by the onset of sea floor spreading which caused a dramatic resurgence in continental drift, culminating in the gradual breakup of the supercontinent. This process continues today.

Along a line appoximating the location of the Equator, North America and Eurasia split away from South America and Africa.

Later, South America separated from Africa and finally North America separated from Eurasia.

The continents also traded bits and pieces of each other along the way. Florida and parts of Georgia and South Carolina, for example, are left-behind fragments of African Gondwanaland.

EARTH WHEN DINOSAURS
BECAME EXTINCT

By the end of the Cretaceous Period the dinosaurs had all but vanished from the face of the earth. 

South America and Africa split into separate continents, creating an ever-widening Atlantic Ocean as they drifted apart.

North America and Europe were still joined to each other near the Arctic Circle, but not for long. India split from Africa and assumed a collision course with China.

See a global animation of continental drift starting 150 million years ago (courtesy of GEOMAR).

The concept of moving continents, once scoffed at by geologists, has today become generally understood and almost universally accepted. Although proposed nearly a century ago, continental drift became accepted only after intriguing evidence from mapping of undersea mountain ranges during World War II and subsequent studies of the ocean floor and continental margins produced nearly irrefutable evidence.

Just what produces the awesome forces that can split and move the continents is still an ongoing process of discovery today.

The study of continental drift, it's history and the forces that cause it, constitutes the branch of geology known as Plate Tectonics.