The Appalachian Mountains are the oldest mountain chain in North America, and are the worn-down remains of a once huge mountain chain. The birth of the Appalachian ranges was 480 million years ago during the Ordovician Period. It was the first of several mountain building plate collisions which made the supercontinent Pangaea. The Appalachians were at the center of the newly formed Pangaea.
North America and Africa were connected, and the Appalachians were part of the same mountain chain as the “Anti-Atlas” or Little Atlas Mountains in Morocco. This mountain range, known as the Central Pangean Mountains, extended into Scotland, from the North America/Europe collision.
They once were as high as the Alps and the Rocky Mountains. The Appalachians are much older than the Rockies, North America’s other mountain range. Due to this, they have eroded over time and are now much shorter on average than the Rockies.