Pangaea - About 250 million years ago the continents were all gathered together into one large continent. We call this land Pangaea, meaning all land. The collisions produced many mountain ranges including the Appalachians and Urals.
The continents will certainly continue to drift in the future. Some scientists think that continental drift happens in cycles. They predict that over the next 250 million years the small continents will gather together once more into a supercontinent like Pangaea.
About this time many plants and animals died. Some people think an ice age may have caused this mass extinction. The ice age could have been caused by the mountains and the position of Gondwanaland over the South Pole.