Part 3/11:
To comprehend how the Appalachian Mountains formed, we need to journey back to 500 million years ago during the Cambrian period. At this time, Earth's landscape was vastly different; life was primarily aquatic, with the first land plants and animals yet to evolve. A critical event in the formation of the Appalachians was the collision of a thin slice of land known as an island arc with Laurentia, which would become North America. This collision marked the beginning of what is called the Tonic Orogeny, setting the stage for mountain building.